The NATO summit in Ankara was designed to highlight member states' expanding defence budgets and commitment to supporting Ukraine, but President Trump redirected the agenda by authorizing military strikes against Iran on Tuesday evening. The strikes responded to attacks on merchant ships in the Strait of Hormuz and included revoking Iran's international oil sales license, occurring immediately after Trump departed a diplomatic dinner with alliance leaders.

The military action exposed fractures within the alliance regarding Trump's expectations for allied participation in operations against Iran. Italy, Germany, and France had previously declined to provide military bases for such missions. NATO officials had anticipated that the announcement of $1.2 trillion in increased defence spending since 2017 would address Trump's concerns about burden-sharing, but his strikes and references to unresolved grievances suggested the summit would remain troubled.