Naturally, some of the Cruz and Kasich dissidents will ultimately return to the Republican fold, and Trump’s campaign, before November. It is normal in a primary for animosities against the winner to be highest at the point a candidate concedes. The prospect of the opposing party winning the White House will soothe many wounds.

There are two factors in this campaign that are unprecedented, though. First, Trump has dispatched his rivals with more personal, rather than substantive, attacks than is normal in recent campaigns.

Perhaps the weirdest moment of the entire campaign was Donald Trump’s bizarre attack on Ted Cruz’s father Tuesday morning, claiming he was possibly involved in the assassination of John F. Kennedy. It strains credulity to even address such a reckless and wild allegation.

That Trump’s attack came on the day he was widely predicted to win the Indiana primary and solidify his position as the presumptive nominee made it particularly tone-deaf. At the precise moment Trump ought to have been trying to unify support from his challengers, the attack will likely leave a lingering, unpleasant aftertaste.