The animosity between Jimmy Carter and Helmut Schmidt is legendary. One crisis, however, which was arguably largely responsible for setting the tone of this relationship has been mostly forgotten: the debate over the German–Brazilian agreement on nuclear co-operation, which envisioned the export of a full nuclear fuel cycle to Brazil. Analysing this crisis not only allows us to examine both countries’ approach to nuclear proliferation in the 1970s, but also their attitude towards transatlantic relations. The crisis showcases the changed international environment of the late 1970s, a weakened United States, an emboldened Germany, and the potential and pitfalls of a ‘uniting’ European continent.