The United States should stop financially supporting NATO allies that fail to support the alliance credibly. To do so, President Donald Trump should relocate a U.S. naval air base in Spain to Greece. He should also transfer Air Force and Army units out of Italy to Poland. The incoming German government has suggested it will dramatically increase defense spending. If it fails to do so significantly and sustainably, Trump should also relocate U.S. forces out of Germany to Poland.

The overriding purpose of these relocations should not be to punish Spain and Italy. Instead, it should be to make clear that the U.S. will now prioritize allies that actually care about the fundamental ingredient of this defensive alliance: mutual burden-sharing.