![Putin's war in Ukraine has pitted Russia against NATO and the US.](https://www.worldpoliticsreview.com/wp-content/uploads/2023/06/putin-war-ukraine-russia-nato-us-aid-europe-taiwan-china-06162023-1.jpg?w=519&h=259&crop=1)
What happens in Ukraine will not stay in Ukraine. That is the essence of an argument commonly made for why the U.S. must support Kyiv in resisting Russian aggression: A failure to stop Russia will give other powers the impression that they can pursue their interests with aggressive impunity. But is that really the case?