From a certain relevance in the second half of the 20th century, albeit episodic and with a domestic focus, subnational diplomacy in the United States has moved with the new millennium towards fresh, more complex and sophisticated, multi-actor frameworks that have greater potential impact. They are frameworks in which certain philanthropic organisations, the private sector, highly influential think tanks and academia carry considerable weight. Today, Ambassador Nina Hachigian, US special representative for city and state diplomacy, leads a strategy looking to gain influence in the State Department and thus make subnational governments key components of the United States’ diplomatic machinery. It remains to be seen how the strategy will evolve, all the more so with the prospect of Donald Trump on the horizon.