The Fundi‐Realo controversy in European green parties stems from unresolved ambiguities in their ideology and strategy. The problem for the green parties is that the very areas that are most ambiguous, such as the balance between parliamentary and extra‐parliamentary politics and the plurality of social movement issues, are the strongest basis of their claim to have developed an innovatory politics. Their common radical democratic ideology produces different issues and debates in each of the four parties examined here and this suggests that national ideological traditions, as well as institutional variables, are important for a comparative explanation of the nature of Fundi‐Realo conflicts.