Secretary of State Marco Rubio offered what may be the clearest articulation yet of the Trump administration’s transactional NATO doctrine — and its implicit breaking point. Speaking publicly, Rubio reframed the alliance’s foundational logic: the United States didn’t join NATO merely to serve as Europe’s security guarantor. It joined, in part, because a permanent military footprint on European soil advances American strategic interests — forward deterrence, power projection, logistical depth. The bases in Germany, Italy, the United Kingdom, and elsewhere are not charity.