Commentary Kids say the darndest things. So does President Joe Biden. Maybe the darndest of the president’s many darn expostulations (I confine myself to those that are intelligible) was his warning last week that the 2022 elections “easily could be illegitimate.” Why would the president of the United States—joined by his vice president, Kamala Harris—preemptively warn that an election some 10 months in the future might be illegitimate? Because, like the rest of the Democratic faithful, the only elections he regards as legitimate are ones that the Democrats win. Thanks to Senators Kyrsten Sinema (D-Ariz.) and Joe Manchin (D-W.Va.), who broke ranks and voted against Sen. Chuck Schumer’s effort to gut the filibuster, the Democrats’ effort to nationalize presidential elections failed. That’s a win for the Constitution, of course, which vests the power to determine election rules in the state legislatures. It’s a loss for the Democrats, though, because it …