For the last four years, policymakers in Washington and European capitals have been consumed by a single question: how to respond to Russia’s full-scale invasion of Ukraine. Their focus is understandable. Russia’s attack on its neighbor is the greatest threat to European security since U.S. and Soviet tanks stood off in Berlin over 60 years earlier. As a result, NATO allies have sent Ukraine hundreds of billions of dollars in military, economic, and humanitarian assistance to prevent it from