The “first 100 days” was a dictatorial metaphor from the start. It entered the presidential lexicon in 1933, when journalists likened FDR’s legislative onslaught to Napoleon Bonaparte’s 1815 breakout from Elba and subsequent three-month rampage, ending at Waterloo. Thankfully, President Trump’s first 100 days haven’t been nearly so dramatic. It’s as if Napoleon, instead of marching to Paris and then to war, just sat around his Tuscan villa, hand in his waistcoat, ranting about his enemies. Of the umpteen items in Trump’s “100-day action plan,” unveiled last fall in Gettysburg, Pennsylvania,...