The shock-and-awe financial sanctions on Russia have rekindled an old trope: that the weaponization of the dollar will end its role as the global reserve currency. Why would foreign countries use dollars, the argument goes, if the dollar can be turned against them? Why wouldn’t China, soon to be the world’s largest economy, build the renminbi into a rival reserve currency? And if not China, what about crypto? This dollar defeatism is vastly overblown. Russia, China and other U.S. adversaries would love to escape the financial hegemony of Uncle Sam. But they have been trying for years and have little...