Free and fair elections across America dodged a bullet this week. A fringe legal theory that former President Donald Trump’s supporters tried to use to help overturn the 2020 presidential election was put before a U.S. Supreme Court that, based on its recent conservative activism, seemed at least potentially apt to endorse it. It didn’t, and the 6-3 majority decision that included all three liberal justices and three conservatives was a sweeping repudiation of a truly dangerous proposition. But the fact that such a radical idea even got this far should give pause regarding the radical times in...