John McCain is demonstrating yet again that he still might be angry at Donald J. Trump’s insulting assertion during the 2016 campaign that the former Navy pilot is a “war hero only because he was captured” by the enemy during the Vietnam War.

Whatever the motive, the Arizona Republican U.S. senator is on point with this declaration: Either provide proof that former President Obama wiretapped your offices during the 2016 campaign or retract it.

The president has done nothing to suggest he has a shred of evidence to back up his scurrilous contention that Obama ordered a wiretap. He has essentially defamed his predecessor by accusing him of committing a felony.

Trump has all the intelligence capabilities available to him to deliver the goods. He hasn’t. Absent any “goods,” he needs to take it all back, admit what many of us know already — that he sought to divert attention from the Russia election-meddling matter.

But, wait! The two things — allegations of Russian meddling and the wiretap allegation — are related!