Paradoxically, Russia’s waning power opened new avenues of influence. The collapse of the Soviet Union was an existential crisis for the Western alliance. In 2003, the Belgian prime minister wrote: “As long as Soviet divisions could reach the Rhine in hours, we obviously had a blood brotherhood with our cousins overseas. But now that the Cold War is over, we can express more freely our differences of opinion.” During the 2011 Libya campaign, President Barack Obama criticized allied “free riding,” and Trump has described nato as “obsolete.” Meanwhile, Russian weakness may have helped undermine the European Union and encourage Brexit. The disappearance of the Soviet Union didn’t just weaken the Western alliance—it also helped sow divisions within the United States. While factors such as globalization, automation, and immigration certainly helped increase polarization and partisanship in American politics, without a common enemy, American politics soon became even more divided.