Judged solely by national polls, Donald Trump has a virtual lock on the Republican nomination. The sense of inevitability that accompanied his entry into the race, then waned a bit as Florida Gov. Ron DeSantis immediately grabbed a quarter of the primary electorate and looked to be surging, has returned. The latest New York Times/Siena College poll showed him earning 54% of the vote and beating DeSantis, battered by stagnant polls and campaign missteps, by 37 points. Call it a coronation after all? The problem with conceding the race to Trump even now is that the opening DeSantis tried (and still tries) to capitalize on is still there. Six months ago, Trump looked anemic in those same national polls, with his numbers much closer to 40%. And in the early states Iowa and New Hampshire,...