On Monday, fake Republican Senator John McCain gave a speech in which he criticized “half-baked nationalism,” which he associated with President Trump. It was a sad attack by a man who has been little more than a Democrat for dozens of years now, but of course, Trump felt forced to fight back. And he did so in typical Trump style.

Appearing on WMAL in Washington, D.C., the president was asked what he thought of McCain’s attack on the “half-baked, spurious nationalism” that’s “cooked up by people who would rather find scapegoats than solve problems.”

Well, Trump said, McCain better be careful. “People have to be careful because at some point I fight back,” the president explained. “You know, I’m being very nice. I’m being very, very nice. But at some point I fight back and it won’t be pretty.”

It doesn’t happen often that a sitting president attacks a prominent senator of his own party so publicly and aggressively, but of course, McCain has absolutely no one to blame but himself. He has been attacking Trump relentlessly from the very first moment Trump announced his candidacy for the Republican presidential nomination. And instead of backing Trump once he became the Republican Party’s nominee, McCain simply stepped up his efforts to undermine him.

Time and again McCain has resisted and actively opposed Trump’s agenda. He voted against Republican efforts to repeal ObamaCare this past summer. He wasn’t the only Republican to do so, but his certainly was a key vote.

Add to that this war of words and McCain can be darn sure that Trump isn’t goofing around. If the RINO from Arizona wants to take Trump on, he’d better expect the president to fight back.

Oh, and if I were McCain, I’d tread very carefully right now. After all, if Trump has proved one thing these last two years, it’s that he is uniquely able to take on and defeat the Republican establishment of which McCain is a proud and prominent member.