The most prominent pretext Vladimir Putin has used for his full-scale invasion of Ukraine is the NATO membership promised to Ukraine and Georgia in 2008. Putin has said again and again that NATO is a threat to Russia, and demanded, in December and again in his pre-war ultimatum this week, that the alliance roll back its troops to where they were in 1997, two years before NATO expanded to Central Europe. In this, he is in a way supported by some respected American foreign policy commentators—Tom Friedman, John Mearsheimer, and others—who…