Now it gets interesting.

Last night's overwhelming victory by Donald Trump -- five states won, pulling anywhere from 54 to 64 percent of the GOP vote, dominating the delegate count -- left the forlorn #NeverTrump movement standing with its pants around its ankles.  For Ted Cruz, the night was even worse. He has been trying to make a claim as the party's legitimate heir to the nomination, but in four of the five states contested last night, Cruz finished last, behind John Kasich, drawing an average of 16 percent of his party's backers. He gave his supporters no reason whatsoever to believe that he is capable of stopping Trump.

Afterward, Trump declared himself the presumptive nominee, and for once in this campaign he got something right: He is the presumptive nominee. Something could happen to change it, I suppose, but given the breadth and scope of his victory last night, it's hard to say what that something could be. The aura of the inevitable winner has begun to settle on his shoulders.

"I think the party is seeing me (as the nominee)," he said in last night's victory speech. "I'm getting calls that you would not believe. I can't even know how they can do it, because they have said such horrible things about me. Now they want to join the team. ... I actually say, how can you do this? And they have no problem."

Yup. That's how power works, and Trump knows it in his bones.   In the wake of these victories, a lot of Republicans who have despised him and everything that he stands for will suddenly begin to see hidden virtues in him. It's as if the magnetic polarity suddenly switches, and what you had found repulsive you now find hugely attractive. They'll be coming out of the woodwork now to kiss his ring and seek his favor. And Trump will enjoy their courting immensely.

Some Republicans will still resist the magnetic pull, of course, and good for them. That is their duty as patriotic Americans. But as chances recede of blocking Trump's nomination prior to the convention, their options shrink. They'll be forced to sit out the campaign, or they can try to rally around a third-party candidate. Given how hapless the anti-Trump movement has been to date, I don't think he's terribly frightened by the prospect.

And we do know that with Trump as the party leader, the 2016 campaign between now and November will be about Trump. We're not going to be debating foreign-policy approaches or economic strategies, it's all going to be about Trump, and to a lesser degree about Hillary Clinton.

This is what the GOP has brought upon itself, not just its leadership but its childish, petulant base. As the philosopher Isaiah Berlin put it in another context, they have sought "the satisfaction of their own emotional needs over and above the attainable goals of the cause they supported," and Trump is the embodimentof that self-centered grandiosity.

This could very well be the end of the Grand Old Party as we have known it, and it is absolutely amazing.