No one should be surprised that Trump’s allies would stoop to dirt-digging. During the campaign, after all, his son, Donald Jr, responded with glee when he learned that a Russian lawyer might have a nice pile of dirt on Hillary Clinton. “Love it,” he exclaimed after learning of the potential trove. The subsequent Trump Tower meeting that took place with the lawyer, also involving Jared Kushner and Paul Manafort, is of keen interest to Robert Mueller.

More broadly, Trump’s mad desire to denigrate Obama shows his fundamental insecurity. It calls to mind his ridiculous, early lie that his inaugural crowd was bigger than his predecessor.

Insecurity is also partly what drove Johnson and Nixon crazy about the Kennedys and their need to tarnish the halo of the assassinated JFK. They couldn’t stand the country’s love affair with its slain leader, just as Trump can’t stand attention being focused on the legacy of Obama, which looks better and better every day that Trump is in office.