Marco Rubio has finally admitted that he was going to lend his support to Donald Trump, saying that if he were asked to speak on behalf of Trump at the Republican National Convention, he would be happy to do so. This wasn't unexpected, but rather just another step in the long, shambling denouement of the entire Rubio persona.

Some are pointing to Rubio's concession as spectacular hypocrisy, not just because of the forcefulness of his previous attacks on Trump (which alone were unusual during a primary campaign), but because of the specific grounds on which those attacks were based. They really were quite incredible: Rubio darkly warned of the consequences of Trump encouraging violence at his campaign rallies, alluding to the "dangerous and disastrous" movements that have arisen out of this kind of political rhetoric. He compared Trump to "third-world strongmen" whose leadership inevitably results in failed states. He called him a "con man" four times in 15 seconds, and most dramatically, a "lunatic" and "erratic individual" who shouldn't have control over the nuclear codes.

Now, after all of that, Rubio said that he'd be "honored" to help unify the party behind Donald Trump, that he'd be "honored" to help the man he called an unhinged tinpot dictator come to power.

He justifies this by saying that he stands by his earlier criticisms of Trump, calling them mere "policy differences" — a gymnastic masterpiece of elision and euphemism that would be funny if it wasn't being employed in service of fluffing a fascist. To be sure, Rubio attacked Trump on his policy bona fides as well, saying that Trump "has never been and is not now a conservative," and that he was attempting a "hijacking" of the GOP. This raises another question: If Rubio believes that Trump is a megalomaniacal lunatic to whom we grant access to the nuclear codes at our own peril and that he's not even a true conservative, on what possible grounds does he justify lending his name and support to him? Hillary Clinton ain't a conservative, either, but the Republican line on her is that she's a standard-issue corrupt Democrat. There is nothing Rubio can say to attack her that will make her sound worse than an insane person who can't be trusted with nuclear weapons.

It's hard to imagine a way to reconcile or rationalize Rubio’s position, which is why his recent meltdown on Twitter, which began with a shot at a journalist and spiraled out from there, was so embarrassing to watch.

The infinitely useful German language has a precise word for this kind of vicarious embarrassment: fremdscham. I felt fremdscham watching Rubio claim that choosing Trump as his vehicle for defeating Hillary wasn't tantamount to supporting Trump.

It's easy to summon a lot of righteous anger at Rubio for his level of hypocrisy here. It's shooting fish in a barrel, and shooting fish in a barrel is both fun and cathartic every once in awhile. But to me, the problem with Rubio isn’t just that he's a hypocrite -- complaining about hypocrisy in politics is like going into the forest and complaining about weeds. Rubio's problem is the same problem he's always had — he doesn't think things through. As much as he is caricatured as a political robot, Rubio is terrible at making calculations.

His signature accomplishment in Congress is emblematic of this failure to think ahead. He pursued immigration reform, not just because it was an issue he cared about, but because he wanted to be a great unifying leader that took heat from his own party for standing on principle. But when the inevitable criticism came from conservatives who called his bill amnesty, he backed away from his own ideas in apparent bewilderment, disowning the bill and eventually justifying his support for it on the hilarious grounds that he never actually expected it to become law. He wanted to be seen as brave, but he never wanted to have to be brave.

Rubio's current impossible position is a result of the same lack of political foresight. He wanted the mantle of the truth-telling prophet, but he was unwilling to resign himself to that prophet’s usual fate: exile or martyrdom. He never expected that he'd actually be called upon to follow through with his convictions; he didn't think far enough ahead for that. And remarkably, he's decided to emphatically repeat his mistake.

Rubio is gambling that he was wrong, that Trump won't actually be able to do the things that Rubio warned Trump would do if he came to power. And he's sealed his fate by handcuffing himself to the fate of Donald Trump and throwing away the key. The best Rubio will be able to say for himself, whether Trump wins or not, is that he tried to help torpedo the American experiment and failed. The worst is too terrible to think about.