President Trump had wrapped up his thoughts on trade with Mexico and was ready to move on with his Monday. But there was an interruption from the media: “Any thoughts on John McCain?” a media representative asked at what’s known as a “pool spray.” No thoughts, as it turned out. The president folded his arms tightly on his chest and mouthed, “Thank you” — a signal that he wasn’t going to bite.

Nor did he bite during two other pool sprays — neither in a meeting with Kenyan President Uhuru Kenyatta, nor in an expanded bilateral meeting with Kenyatta.

These are by no means idle queries: McCain was among the few Republicans in Washington to denounce Trump’s depraved politics and abhorrent personality; he also helped to deprive Trump of a legislative victory when he voted last year against an Obamacare repeal measure. He also endured Trump’s calumny during the presidential campaign, when the hopeful discredited his service in the Vietnam War.

After news broke over the weekend of McCain’s death, Trump issued a tweet that omitted any praise of the senator’s decades of U.S. service: “My deepest sympathies and respect go out to the family of Senator John McCain. Our hearts and prayers are with you!” But that tweet aside, he didn’t want to talk about McCain, as ABC News White House correspondent Jonathan Karl noted in a series of tweets on Monday:

For Trump’s recent predecessors, the silence before eager reporters in pool sprays would be a normal state of affairs. Martha Kumar, director of the White House Transition Project, determined that through the end of April 2018, Trump had done 170 short Q-and-A sessions, as opposed to 55 under President Barack Obama in the same time frame. Trump’s tally swelled to 233 as of Aug. 22, Kumar noted. One of those 233 occurred on Aug. 11, when Trump commented that Omarosa Manigault Newman, a former aide and author of a new book on Trump, was a “low life.” Which is to say: Trump can be bothered to insult an ex-aide, but not to say anything statesmanlike about a long-serving senator.

The president’s extraordinary openness on these occasions — a trait that, in the eyes of his critics, underlines his lack of discipline — contrasts with his tight-lipped demeanor on Monday. This is a man who just doesn’t want to talk about McCain.

As The Post reported, Trump rejected plans to issue a statement over the weekend praising McCain, though pro-decency forces at the White House appeared to have prevailed by Monday afternoon. “Despite our differences on policy and politics, I respect Senator John McCain’s service to our country and, in his honor, have signed a proclamation to fly the flag of the United States at half-staff until the day of his interment,” reads the statement, in part.