How to promote sustainability? The challenge of strategic spatial planning in the Vietnamese Mekong Delta

ABSTRACT Tropical river deltas such as the Amazon, the Ganges-Brahmaputra-Meghna, and the Mekong are facing increasing pressures from climate change, upstream infrastructure building, and rapid economic development. Many deltas are shrinking and sinking, risking national and global food security. To promote the sustainability of the Vietnamese Mekong Delta, the Vietnamese government has developed a strategic spatial plan that introduces legal and institutional innovations designed to recalibrate central-local relationships and to increase policy effectiveness. We analyse these strategic changes by drawing on three sets of literature: strategic spatial planning, environmental states, and sustainability transitions in multi-level governance systems. We conducted interviews with provincial government officials in the delta to provide fresh insights into the real-time changes that local officials are facing. Our findings suggest that the state remains crucially important to facilitate transitions towards sustainability. By analysing the ongoing restructuring of state-wide governance regimes and resource relationships across a multi-level playing field, we view the state as a dynamic multi-level system where the dispersal of power is constantly in motion. Such a view allows us to observe in real time how states cope with sustainability crises. Applying this to the Vietnamese Mekong Delta enables us to locate the delta within a changing state-wide multi-level governance structure for strategic spatial planning in which the Vietnamese government enacts policy innovations to build local capacity while binding provinces closer to the centre. This recalibration of central-local relationships needs to be underpinned by investment in staff, the mobilisation of financial resources, and detailed guidance for implementation in order to stabilise the vertical and horizontal governance structures that are developing to transition vulnerable landscapes into a sustainable future.


Introduction
Large tropical deltas such as the Irrawaddy, the Amazon, the Mekong, or the Ganges-Brahmaputra-Meghna are key agricultural areas that contribute significantly to local livelihoods, national economies, and global food security (Hagenlocher et al., 2018;Loucks, 2019;Szabo et al., 2016).The sustainability of river deltas is crucial.Although deltas represent only one percent of the global land area, they are home to half a billion people (Kuenzer & Renaud, 2012).Governments are increasingly developing strategic delta plans to build longterm sustainability for these vulnerable landscapes.The aim of such strategic spatial plans is to transform large landscapes to reconcile economic growth and sustainability.The Bangladeshi government's and the Vietnamese government's delta plans are two prominent examples that attempt to create sustainability in the face of multi-scale challenges.
By reimagining delta spaces and attempting to overcome policy and institutional fragmentation, governments view strategic spatial plans as potentially important tools that could help promote long-term sustainability (Gustafsson et al., 2019); but strategic spatial plans also represent an attempt of states at renewing their legitimacy in the face of environmental degradation (McElwee, 2016;Weger, 2019).The context of progressive global environmental decline and the climate crisis provides a critical juncture to understand the interplay between strategic spatial plans and the role of the state to enhance the sustainability of critical landscapes.
This article explores these dynamics in Vietnam, with a focus on how strategies to enhance sustainability have in recent years become manifest in changing discourses, policies, and governance structures in the Vietnamese Mekong Delta (VMD).We draw on three sets of literature: (i) on strategic spatial planning, (ii) on environmental states, and (iii) on sustainability transitions in multi-level governance systems.In so doing, we take up the challenge posed by Duit et al. (2016, pp. 14-16) to develop a deeper understanding of the role of the state in managing sustainability transitions.
The VMD produces almost 20% of the world's rice supply (Smajgl et al., 2015).However, a combination of mutually reinforcing dynamicssea level rise, seawater intrusion, droughts, sand mining, shrinking groundwater tables, erosion, pollution, upstream infrastructure building and storm surgesis threatening the future of the region.The VMD shares a fate with other global deltas: it is shrinking and sinking (Boretti, 2020;Parker, 2020; Van et al., 2023;World Bank, 2021).
To cope with these problems, the government has devised a strategic spatial plan for the VMD.This began with the publication of the 2013 Vietnamese-Dutch Mekong Delta Plana reference document to guide strategic delta developmentand culminated in the 2022 Mekong Delta Master Plan.This decade is the empirical focus of the article.The plan requires the willingness of delta provinces to comply with central legislation and the ability to enforce them locally.Provinces are responsible for implementing central government legislation in their jurisdictions (Seijger et al., 2017).They are, therefore, at the intersection of top-down enforcement and bottom-up resistance within a system that has been termed 'hierarchical multilevel governance' (Phuong et al., 2018, p. 519).
To understand how strategic spatial plans operate in such an environment, we draw on Ehnert et al. (2018) who explored the role of local governments in sustainability transitions within a multi-level governance context.We ally this perspective with two bodies of work: firstly, on the environmental state that aims at 'bringing the state back in' to environmental governance (Chandrashekeran et al., 2017;Duit et al., 2016); and, secondly with work that explores strategic spatial plans not merely as managerial tools but as re-imaginings of space (Walsh, 2021).Combining these perspectives helps understand how states attempt to manage sustainability transitions by fashioning new and innovative governance arrangements that foster vertical and horizontal collaboration.For our focus on the VMD, we draw on fresh empirical insights from interviews with provincial governments, allowing us to understand in real-time how officials navigate a complex set of actors and policy issues across multiple levels of governance.

Strategic spatial planning and the role of the state in sustainability transitions
Strategic spatial planning aims at improving sustainability by overcoming institutional fragmentation and integrating policy arenas between and across scales (Demazière, 2018;Gustafsson et al., 2019;Wilkinson et al., 2013).As such, strategic spatial plans create new governance frameworks through political and institutional restructuring, resulting in 'multi-level and multi-actor governance arrangements' (Albrechts, 2001;Getimis, 2010, p. 123;Tewdwr-Jones, 2002).
Strategic spatial planning, however, is not simply a managerial process: space is 'reworked and re-imagined' (Walsh, 2021, p. 818), involving the enactment of 'spatial imaginaries' (Baker & Ruming, 2015) and the creation of new 'spatial identities' (Albrechts, 2001, p. 293) for the future development of a region (Healy, 2007, p. 226).This process involves the discursive framing and institutional creation of new environmental spaces and boundaries (Cowell, 2010, p. 222;Walsh, 2021, p. 819), leading to the emergence of new spatial-environmental geographies (to borrow from Ehnert et al., 2018, p. 102).Strategic spatial plans, therefore, represent qualities of landscapes in particular ways that legitimise a set of interventions for the purpose of socio-economic transformation (Cowell, 2010, p. 223).
It is these transformative agendas that lead us to consider the state as a central analytical category.We do this by drawing on Duit et al. (2016) who developed the concept of the 'environmental state' to explore how states manage sustainability transitions.The authors argue: A focus on the environmental state [puts] the agency of the state, as well as historically defined patterns of state institutionalisation that structure political interaction, into the spotlight.By adopting the state as a central analytical category, researchers can explore its role in the constitution and reproduction of governance arrangements, the stabilisation of framework conditions for everyday routines, and the organisation of networks and flows.It helps to focus attention on the venues and processes of the authoritative determination of contested social arrangements (pp.3-4).
Such a focus allows a better understanding of how states are '"doing" environmental statecraft' and the 'material manifestations of environmental statehood' in the shape of institutions and practices for sustainability (Chandrashekeran et al., 2017, p. 3).For us, the 'constitution and reproduction of governance arrangements' is especially helpful to understand changes in VMD governance.It also emphasises the strategic nature of such undertakings, including the need for restructuring across a multi-level system.Recent analyses of the environmental state have focussed on such processes in liberal democratic states.This literature emphasises the limitations of such states in bringing about transformative change (Biermann, 2021;Doebeli et al., 2021;Eckersley, 2021;Hausknost, 2020).This focus, however, overlooks that sustainability transitions have also been occurring in hierarchical states against the backdrop of social and economic shifts, including economic liberalisation and globalisation; the rise of middle classes; and environmental degradation.For our analysis of Vietnam and the VMD we are therefore less concerned with the limitations of environmental states, but rather with their emergence in new, non-liberal contexts, and the ways in which innovative discourses and governance mechanisms unfold across multiple levels of governance and the challenges it produces for established hierarchies.It is these concerns that we turn to next.

Strategic spatial planning in hierarchical systems
The multi-level character of strategic spatial plans requires collaboration between a wide range of actors across a multi-level playing field (Baird et al., 2019;Bodin, 2017).This poses particular challenges for hierarchical states, where we see ambitious government programmes for sustainability transitions amidst the evolution of multi-level governance frameworks (Hensengerth and Lu 2018).Phuong et al. (2018, p. 519) referred to this phenomenon as 'hierarchical multi-level governance.'In such contexts, we see an ongoing reform of central-local relationships as central governments create new financial incentives, training programmes, or governance mechanisms to increase the capacity of local governments while simultaneously binding them closely to the centre (Yang, 2017;Zhang et al., 2020).At the core of these reforms is the question of how to reform but maintain what Eckersley (2017:, p. 84) referred to as 'vertical power dependencies.' Central-local relationships are often captured through the concept of multi-level governance.Multi-level governance was originally developed to understand policy processes in the European Union (Marks, 1992).The concept enables a 'focus on the shift from a unified authority, acting rationally at the centre of government, towards a diffusion of power' across subnational and non-state actors (Cairney, 2012, p. 155).Since its birth, the concept has gained widespread popularity, including amongst scholars of sustainability transitions to the extent that Zapata-Barrero et al. ( 2017) identified a 'local turn' in the literature on multi-level governance.This local turn describes a focus on the role of subnational governments to achieve sustainability.While this local focus has allowed important knowledge production on the role of local governments, it has also led attention away from state-wide perspectives, including the enduring role of central governments.
Understanding these central-local dynamics requires refocussing on the state as a whole; not, however, by black boxing the state but rather by understanding how different actors interact in the management of transitions and what this tells us about how power is dispersed (Johnstone & Newell, 2018, p. 79).Helpful for understanding the state in this manner are Ehnert et al. (2018) who explore 'how wider multi-level governance structures shape the agency of local actors' during sustainability transitions (p.102).Key to their understanding is the mobilisation of hard and soft power resources dispersed across a multi-actor and multi-level playing field, whereby the distribution of hard and soft power 'is partly shaped by the multi-level governance context which includes the institutional structures of the political system within which actors operate' (Ehnert et al., 2018, p. 104).The authors distinguish between federal and unitary states.The latter are characterised by centralised political systems where central governments are the principal decision-making authority and where subnational governments are comparatively weak.This is useful for us, as Vietnam counts amongst the range of unitary states (Hartley et al., 2020).Ehnert et al. draw on Stoker (2011: 27) in their definition of power: hard power is 'the power of command and incentives' and soft power is 'the power to get other people to share your ideas and vision' (Stoker 2011: 27 cited in Ehnert et al., 2018, p. 104).In this sense, hard power 'is the power of coercion, regulation or economic incentives whereas soft power is expressed through values, ideologies and ethos' which can be invoked to rally political support and create legitimacy for transitions (Ehnert et al., 2018, pp. 104-105).In terms of hard power, in unitary political systems 'the constituent units (e.g.local municipalities) can only exercise those powers that the central government has delegated to them and the national government can reconfigure the dispersion of authority unilaterally' (Ehnert et al., 2018, p. 105;Hartley et al., 2020).In such vertical power relationships, the distribution of resources from the central government to local actors is key to create local government capacity, but also to ensure local government continues to rely on the central government (Eckersley, 2017).This may encompass money, training and technical guidance.Soft power, in contrast, is more readily available to actors other than central governments, enabling a more complex top-down and bottom-up dynamic (Ehnert et al., 2018, p. 106).
By viewing the state as a dynamic multi-level system where the dispersal of power is constantly in motion, we can observe in real time how hierarchical states attempt to cope with sustainability crises.We will now turn to analyse how these dynamics unfold in the context of transitioning the VMD into a sustainable future.

Methods
We began our research with a policy review to observe the changing policy and governance context in VMD.Our focus fell on key decisions in the context of developing the Mekong delta strategic plan.This began with the 2013 Mekong Delta Plan document; and proceeded to encompass the 2016 Decision 593/QD-TTg on Pilot Coordination for Regional Socio-economic Development in the Mekong Delta; the 2017 Resolution 120/NQ-CP on Sustainable Development of the VMD; the 2017 Law on Planning; the 2020 Decision 825 on the Establishment and Operation of a Mekong Delta Coordination Council for the period 2020-2025 and its successor, the 2023 Decision 974/QD-TTg to establish a Regional Coordination Council for the VMD; and the 2020 Decision 1163 that led to the 2022 Mekong Delta Master Plan (for a discussion of key policies see Van et al., 2023).In this process we reviewed national level policy such as the Law on Planning, which applies beyond the VMD; and policies pertaining specifically to the VMD.This allowed us to locate the VMD within a changing state-wide multi-level structure for strategic spatial planning.
What emerged was a picture of a dynamic central-local relationship within a hierarchical setting, in which the central government aims to push VMD provinces towards more collaboration to overcome horizontal fragmentation; to create new mechanisms to overcome vertical fragmentation; and to develop a consensus amongst key actors at all levels for the direction of delta development.However, we still had a lack of understanding of how provincial governments understood these changes.We therefore aimed to gain a greater understanding of the current position of provincial governments in the process of strategic delta development.
To do so, we proceeded to select interviewees in different provincial governments, and one local academic who works closely with provincial governments, based on their involvement in strategic spatial planning since the release of the 2013 Mekong Delta Plan.To gain a wider spectrum of views, we opted for a minimum of two departments per locality: the Department of Planning and Investment as the local lead agency, and at least one more key department.
We then conducted thirteen semi-structured interviews during November and December 2021.We initially contacted fifteen interviewees, of which thirteen responded.We first contacted interviewees via email.This introductory email included the list of questions in order to be transparent about the topics we wanted to discuss.Our questionnaire was divided into three parts: the first part enquired into current central government planning policies.It included questions about key policies currently in use, the major changes these produced, strength and weaknesses, and training opportunities for officials.The second part focussed on the implementation of what was then the draft Mekong Delta Master Plan.Discussion points in this part included the importance for delta sustainability, strengths and weaknesses, and the impact on regional governance.The third part focused on provincial planning and included questions on the capacity of provinces to carry out central policies.Due to the Covid-19 pandemic, international travel to Vietnam was not possible at the time, and travel within Vietnam was restricted.The Vietnamese research team therefore conducted interviews remotely.Interviews were held in Vietnamese and translated into English.The table below shows the final list of interviewees.

Vietnam's hierarchical, multi-level governance
The Vietnamese central government plays a dominant role in policymaking for sustainability (McElwee, 2016).This is despite evidence of globalisation and neoliberalism having eroded some state functions since the economic reform programme of doi moi (renovation) launched in 1986 (Christoplos et al., 2016;Henrysson & Hendrickson, 2021;Phuong et al., 2018).There is certainly evidence that the state is no longer the only actor: nongovernmental organisations (NGOs) help solve environment related issues, the private sector is a source of finance and knowledge, and international organisations and development partners provide external resources (Leitold et al., 2020).The role of provinces has also adapted to the need for integrated planning and more effective policymaking.In the area of the environment, the 2015 Law on Organising the Local Government assigns provincial governments the role of managing state resources and the environment, including land and water.The law further permits provincial governments to release their own regulations, provided they comply with central government objectives.This is part of a process wherein the state has attempted to empower provincial and district governments 'while retaining a firm … grip on overall policy' (Christoplos et al., 2017, p. 451).
These developments need to be seen in terms of what Sending and Neumann (2006:, p. 652) called a 'changing logic … of government', whereby central governments cooperate in a carefully calibrated manner with other actors across a multi-level setting (Bruun & Rubin, 2023).As state legitimacy is now underpinned by goals for environmental protection (Henrysson & Hendrickson, 2021), this requires overcoming problems of policy implementation and increasing policy effectiveness (Huynh, 2016;Tran & Weger, 2018).The introduction of more flexibility, however, has led to 'considerable mismatches between state and non-state […] action' (Garschagen, 2015, p. 599).In the VMD, it has led to continuous 'friction […] between top-down plans and bottom-up action taken by provinces' (Christoplos et al., 2016, pp. 22-23;Minkman et al., 2022).The resultant patchwork of actors and actions makes strategic spatial planning in the VMD a crucial but difficult task.Perhaps foremost of these is the development of a spatial vision that can be shared across central, local, and non-state actors.

Creating a new spatial vision
Between the 1980s and the early 2010s, a one-sided emphasis on structural interventions for rice intensification brought economic growth and national food security (Tran, 2020;Van et al., 2023).This, however, has led to progressive soil and water pollution, biodiversity decline, and riverbank erosion.Furthermore, accelerated upstream dam building has led to a lack of water and sediment discharge, contributing to subsidence, riverbank and coastal erosion, and seawater intrusion.The latter is accelerated by the impacts of sea level rise.In response, people have drawn increasingly on groundwater resources.The cumulative effect is that the delta is shrinking and sinking (Eslami et al., 2019;Gunnink et al., 2021).
These problems are exacerbated by two mutually reinforcing dynamics: a lack of effective horizontal coordination between the delta's provinces, and a lack of a vertical joined-up approach between central and local governments.Strategic delta planning attempts to remedy these issues: plan-making emphasises a more consultative approach; a new regional governance mechanism aims at stimulating horizontal cooperation; and the conflict between ecological integrity and economic growth is to be addressed through a combination of structural and nature-based solutions.
The 2013 Mekong Delta Plan document 'recognises that the orientation for the agricultural sector in the delta needs to shift from a focus on production towards a focus on added value by improving the productvalue chain, involving public-private partnerships and introducing market-based mechanisms' (Socialist Republic of Vietnam and Kingdom of the Netherlands, 2013, p. 7).The creation of this document has a complex history.It is the result of a Dutch-Vietnamese collaboration and is thus a case of international policy transfer (for details on the complexity of this process see Hasan et al., 2019;Weger, 2019;Zegwaard et al., 2019).It functioned as a reference document for the subsequent development in the VMD.The creation of the document was accompanied by extensive consultation sessions between central and local governments, academics in the VMD, international NGOs, and development partners, with general agreement achieved at the end of the process about the new development direction (Seijger et al., 2017;Vo et al., 2019, pp. 13-17).This created a shared vision of the delta's future and provided political legitimacy for the central government.
An elaboration of this plan was presented with Resolution 120/NQ-CP on Sustainable Development of the VMD, released in 2017, and the resolution's action programme of Decision 417/QD-TTg, released in 2019.These presented 'a clear image of the desired end state' of the delta (Minkman et al., 2022, p. 6;Weger, 2019, p. 187).Resolution 120 'provided a foundation for transforming the region's development, from a small and individual household farming and provincial perspective to an inter-provincial, transboundary and delta-wide perspective; from a short-term sectoral perspective to a long-term, multisectoral, and integrated approach' (Nguyen, 2022).
Implementation, however required significant changes to the way the VMD is governed.These changes include national-level policy changes to adapt state-wide planning structures, as well as VMD-specific provisions, to improve vertical and horizontal cooperation.The next section explores these issues in more detail.

Recalibrating central-local relationships
Key to making these changes is the Law on Planning, which was passed in 2017 and took effect in 2019.It created a streamlined system of tiered master plans.The aim was to develop a clear and integrated system for sectoral and geographical planning.The law clarifies that provincial governments are responsible for the management of planning in their jurisdictions and are required to support the formulation of national and regional plans.Regional plans, such as for the VMD, are directly under the Ministry of Planning and Investment, thus creating central government oversight.These provisions, for the first time, regulated regional planning.
The law aims at a multisectoral and interprovincial (spatial) planning approach to improve coherence between socio-economic development and environmental protection in all regions of Vietnam.In 2020, the government tasked the Ministry of Planning and Investment with the development of an integrated spatial plan for the VMD (Decision of the Prime Minister 1163/QD-TTg, 31 July 2020, Approving the Task of Planning the Mekong Delta Region in the Period of 2021-2030, with a Vision to 2050).This was to become the 2022 Mekong Delta Master Plan (Socialist Republic of Vietnam and Kingdom of the Netherlands, 2013, p. 36, 41).The Netherlands offered technical support and the World Bank provided financial aid.It became the first master plan developed under the Law on Planning (Next Blue, 2022;Royal Haskoning DHV, 2022;Vietnam Law and Legal Forum, 2022).
Interviewees unanimously welcomed the new policies, arguing that they provide a clearer system of planmaking and enable better synchronisation of local, regional, and national plans.One government official from Can Tho described the Law on Planning as a 'breakthrough in the development orientation of the country'.An official from Soc Trang argued that it led to a redesign of the spatial planning architecture for the VMD.All considered the master plan essential for the delta's sustainability.Interviewees also stated that their department had been consulted during the formulation of the Law on Planning, although they argued that central government uptake of suggestions was varied.
All interviewees stated that following the release of the Law on Planning and the draft Mekong Delta Master Plan, all provinces had adjusted their planning policies and had released local guidelines for the formulation of provincial plans.This included the creation of intra-provincial multi-stakeholder steering committees.However, difficulties remain for provincial planning: many interviewees pointed to a lack of detailed central government guidance for implementation, which leads provinces to interpret laws differently across the delta.For example, an official from An Giang province pointed out that the Law on Planning describes the content required for planning in articles 22-28, but this is not detailed enough to shape provincial development targets and determine what information is required for provincial plans.A detailed planning manual or guidance document is necessary.One official from Hau Giang province said that the department was waiting for the central government to provide specific details on implementation, such as on land use quotas before land zoning can go ahead.Many interviewees also referred to a lack of trained staff to deal with the technical complexities of the new policies.While all agreed that they had received training and had carried out training for other government departments, officials cited insufficient investment in staff as a key barrier to effective implementation.
To enable regional planning under the Law on Planning, the government advanced an important change in regional governance with the 2020 Decision 825/2020/QD-TTg to establish a Regional Coordination Council for the VMD.This was replaced in August 2023 with Decision 974/QD-TTg to remedy some emerging problems.According to both decisions, the council's purpose is to 'innovate the regional coordination mechanism,' to 'promote sustainable development' and to help 'the Prime Minister research, direct, and coordinate' VMD development.All chairmen of the thirteen VMD provinces are council members, but the central government has significant involvement: the council is chaired by the Deputy Prime Minister, the Permanent Vice Chair is the Minister of Planning and Investment, and the Vice Chairmen are the Ministers for Agriculture and Rural Development; Natural Resources and Environment; and Transport.Funding comes from the budget of the Ministry of Planning and Investment, establishing a clear vertical resource relationship.In contrast to Decision 825, Decision 974 creates a clearer set of objectives, and it explicitly establishes the Ministry of Planning and Investment as the council's standing agency to provide stronger central leadership.
The initial establishment of this body met with mixed views.Having been interviewed approximately a year after Decision 825, interviewees reported that the council does not create a new governance level and therefore has limited political authority.This lack of a regional lead unit to make decisions makes it difficult to resolve coordination problems.Views of the council amongst our interviewees ranged from very positive to having achieved very little.An official from Hau Giang argued that many provinces also have a lack of clarity of what they should cooperate on.An official from Soc Trang pointed to a lack of a regional strategy.The same official argued that while there are many ideas for projects, there is no agreed mechanism for implementation.An An Giang official argued that cooperation often does not go beyond information exchange, with another An Giang official arguing that even the sharing of informationsuch as on environmental pollution or investment activitiesis often ad hoc only.A Hau Giang official complained that instead of cooperating with each other, many provinces are competing.Interviewees, therefore, called for more central leadership.
Funding also remains a problem.In 2016, the Prime Minister's Decision 593/QD-TTg on Piloting Subregional Socio-Economic Development Planning in the VMD for the period 2016-2020 proposed new financial support for regional planning.In 2018 the Saigon Times reported that implementation is lagging behind, amongst the reasons being a lack of financial resources.The lack of a regional budget combined with financial weakness of local provinces and cities -12 out of 13 of the provinces rely on central government fundingare amongst the problems preventing an effective implementation of Decision 593/QD-TTg (Trung, 2018).These concerns were echoed by many of our interviewees, who cited a lack of financial resources as a barrier to carrying out regional tasks.This presents a problem for the Regional Coordination Council, whose budget is determined by the central government.
The problems reported abovea lack of training and funding, ambiguity about the purpose of regional coordination, a lack of central leadership, and insufficient technical guidanceecho Weger's (2019, p. 186) argument that plans in Vietnam need to be accompanied by detailed guidance for implementation procedures and responsibilities; without this, plans may not be realised, and the Mekong Delta plan might stay a 'dream'.Broad stakeholder agreement on policies, therefore, is insufficient to forge ahead with strategic spatial plans.As the central government crafts strategic approaches to sustainability, this ambition needs to be accompanied by significant investment in staff and the mobilisation of financial resources to stabilise the vertical and horizontal governance arrangements that emerge.

Discussion
As states acquire green agendas and develop strategic approaches to sustainability, the role of the state has come back into focus.Duit's (2014) work on the environmental state emphasises the need to understand the restructuring and reproduction of governance arrangements beyond individual policy reforms.These processes play out across multiple levels of governance, and understanding them requires adopting a multi-level perspective.It is for this reason that we brought in Ehnert et al. (2018) to help analyse how such restructuring and reproduction occurs in a multi-level context.
Vietnam's move towards an environmental state is visible as it changes the national planning framework, develops new governance mechanisms, rolls out new financial and training schemes, and seeks consensus across a wide range of actors.As strategic spatial plans need to be implemented across a multi-level playing field, their success depends on better vertical and horizontal cooperation, which in turn requires that key actors share spatial visions.To achieve this in the VMD, the central government has invested significant efforts to create consensus with actors across a multi-level setting for a new spatial vision, the first result of which was the 2013 Mekong Delta Plan reference document.Indeed, it is now accepted within science and policy circles that the sustainability of the VMD can only be addressed through multi-level governance approaches (Van et al., 2023, p. 10).
While the central government remains the key actor, it recognises the importance of provincial governments for achieving sustainability in their jurisdictions.This has engendered a recalibration of central-local relationships designed to allow more provincial input into policymaking and build local capacity.At the same time, these institutional and legal innovations aim at increasing central government oversight, ensuring that provinces continue to rely on the central government rather than becoming more independent actors.A good example is the creation of the Regional Coordination Council, which aims at facilitating cooperation between provinces, but it aims to do so without creating an independent regional governance layer and with a centrally determined budget.This emphasises the importance of vertical resource dependencies in these processes (Eckersley, 2017).
But the recalibration of central-local relationships is not merely technical.It represents 'material contestations over the control of space and resources' (Christoplos et al., 2016, p. 52).Cowell (2010) argued that strategic spatial plans legitimise interventions for the purpose of socio-economic transformation.This is akin to McElwee's concept of 'environmental rule', which refers to interventions that states, organizations, or individuals justify for environmental reasons but which are underpinned by broader rationales for social planning (McElwee, 2016, p. 5).Environmental rule can be understood to represent hard power: the ability of central governments to wield powers of 'coercion, regulation, or economic incentives' (Ehnert et al., 2018, pp. 104-105).The 2013 Mekong Delta Plan and its 2022 incarnation represent an attempt by the central government to increase its control over regional planning through the imposition of new planning processes, new institutions, and capacity-building in the form of training and finance (Weger, 2019, p. 187).
However, the need to create buy-in from across a wide range of actors also shows the need for consensusmaking and thus the need to exert soft power 'expressed through values, ideologies, and ethos' (Ehnert et al., 2018, pp. 104-105).These are backed up by hard power in the form of vertical resource dependencies.In contrast to Ehnert et al.'s suggestion that soft power is more readily available to actors other than the central government, we suggest that in hierarchical systems both hard and soft power are the domain of central governments.Nevertheless, the notion of soft power enables debates about the symbolic struggles that underpin strategic spatial planning (Cowell, 2010;Walsh, 2021).The VMD, therefore, is not only defined by the physical features of its landscape.It is just as much defined by what policymakers want it to be.
By mobilising hard and soft power resources, the state is reasserting itself.By drawing in actors across different levels, the state is not hollowed out; what changes instead are the ways in which states 'exercise political authority' (Ehnert et al., 2018, p. 103).It is perhaps this 'changing logic … of government' (Sending & Neumann, 2006, p. 552) that is important for the creation of the 'spatial imaginaries' (Baker & Ruming, 2015) the making of consensus to create agreement for a spatial vision and to enable its implementation across a multi-level and multi-actor space.However, broad stakeholder agreement is insufficient.While our interviewees were unanimous that the new, strategic approach to the VMD is important, many also argued that a lack of training and funding, a lack of political authority for new governance arrangements, and a lack of guidelines for implementation means that a positive spatial vision is not yet sufficiently underpinned by plans for its implementation.As Weger (2019, p. 186) showed, plans in Vietnam need to be accompanied by detailed guidance to reduce uncertainty during implementation.This emerged clearly from our interviews: despite increasing discretion for provinces over local policy implementation, uncertainty about new central government provisions makes local policy implementation difficult.This echoes Amundsen et al.'s (2010) argument that in hierarchical systems lower administrative units often wait for policy directions from above before deciding on a course of action.This carries significant risk for the future sustainability of the VMD.

Conclusion
We began the article by drawing on three perspectives to understand how states deal with sustainability crises, focusing on major river deltas: strategic spatial planning, the environmental state, and sustainability transitions in multi-level governance systems.These three perspectives help understand the mechanics of turning spatial visions into policies, and the problems that occur on the way.We posited that Duit's (2014) notion of the environmental state as mediating between economic and environmental rationales underpins the very need for strategic spatial plans: to reconcile the conflict between environmental and economic imperatives.We argued that the context of a crisis of sustainability requires focusing on the state as a central analytical category to understand shifts in state-wide governance structures and productions of space.Creating the environmental state, therefore, is a holistic undertaking in which central governments set parameters for development by drawing on hard and soft power resources, but they need to do so with the cooperation of local governments and non-state actors in a multi-level playing field.
Developing and implementing the Mekong Delta Master Plan has seen a coordinated effort by the Vietnamese central government to create consensus amongst key actors, thus attempting to pave the way for vertical and horizontal policy integration and creating legitimacy for the transformation of the VMD.Rather than being merely technical, however, strategic spatial planning is an exercise in placemaking that involves a wide range of stakeholders.This is not only confined to domestic actors: the role of global actorsin our case the Netherlands and the World Bank-is also important, and so is the flow of materials and knowledges that accompany them.In this article, we have focussed on the role of provinces within a domestic setting.We posit that there is space to expand on this research: by enquiring into the ways in which sub-provincial localities implement strategic delta plans on the ground, and combining this local perspective with research to understand the ways in which global flows of trade, investment, and ideas penetrate these local spaces.This would further contribute to a dynamic and multi-scalar perspective of how space is produced and the processes through which vulnerable landscapes may transition towards sustainabilityor may be prevented from doing so.

Disclosure statement
No potential conflict of interest was reported by the author(s).

Funding
We are grateful for the generous support for this research, which was funded as part of the NERC-Newton Fund project VIET NAM: Slow Onset Hazard Interactions with Enhanced Drought and Flood Extremes in an At-Risk Mega-Delta (grant reference NE/ S002847/1).