Donald John Trump Sr.’s grotesque lack of compassion became evident yet again Tuesday night while he was railing against Arizona’s two Republican U.S. senators.

One of them, John McCain, is battling brain cancer. Doctors performed surgery recently to remove a cyst near his left eye and discovered an aggressive malignancy in his brain.

I don’t know what the doctors have told McCain about his prognosis. That’s for the senator and his family to know.

Did the president say a word of concern, or care, or compassion about his fellow Republican? Did he offer any prayers from his family to the senator’s? Did he wish him a speedy and full recovery?

Oh, no. The president ventured onto McCain’s turf — his home state of Arizona — and ranted, raved and ridiculed the senator.

I must add, by the way, that the senator has served his country with more honor, heroism and bravery than the president ever imagined. His experience as a prisoner during the Vietnam War alone would be enough to bestow such high praise.

OK, the president didn’t say it. I’ll offer yet again a good word to the stricken senator. Get well, sir. Thank you for your stellar service to our great nation.