I wrote five years ago about the growing threat of a wealth tax. Some friends at the time told me I was being paranoid. The crowd in Washington, they assured me, would never be foolish enough to impose such a levy, especially when other nations such as Sweden have repealed wealth taxes because of their harmful impact. But, to paraphrase H.L. Mencken, nobody ever went broke underestimating the foolishness of politicians. I already wrote this year about how folks on the left are demonizing wealth in hopes of creating a receptive environment for this extra layer of tax. And some...