And there is another plausible explanation for the vote change: John McCain’s illness meant that Corker could become the deciding vote. While Corker was willing to grandstand against the bill, he wasn’t actually willing to block it.

Which is exactly what I find so damning.

Corker had previously said that if the tax bill added “one penny to the deficit,” he wouldn’t support it. He also denounced the budget gimmicks in previous versions of the bill that were designed to obscure its true fiscal effects. Yet he is supporting a final version of the bill that will add something like $1 trillion to the deficit over 10 years, according to independent analyses, even before taking into account its blatant budget gimmicks.

Not only that, but the rush to pass it — without the months of hearings that accompany most complex legislation (yes, including Obamacare) — means that it’s likely full of surprises, like the so-called Corker Kickback, even if it was only a handout instead of a kickback. “The wealthy and well-advised are going to have a field day with all the loopholes created by this bill,” N.Y.U.’s Lily Batchelder said yesterday on Twitter.

Corker is retiring from the Senate after this term, in part, it seems, because he is disturbed by Trump’s behavior as president. His retirement from politics could have freed him to vote his conscience. Instead, he’s violating his own principles, or at least what he calls his principles. It’s sad, and it’s damaging to the country.