THE PARADE WAS A GOOD THING. Here’s the first thing to say about Saturday’s military parade in Washington, D.C., honoring the Army’s 250th birthday: It was a good thing to do. It wasn’t a vanity production for President Donald Trump’s birthday. It wasn’t an authoritarian flex. It wasn’t a threat to the American people. It was, instead, a dignified celebration of one of the great institutions of American life as it, and the United States, marks its 250th year of existence. Trump was right to highlight the Army’s birthday as the beginning of “America250” events. It was also a good...