“This is our due.” So spoke Dick Cheney, according to journalist Ron Suskind, summing up the case for passing more tax cuts even as the United States was embroiled in one war and gearing up for another. One of Cheney’s few gifts was that of expressing the id of the Republican establishment in five words or less (and Trump’s rise has taught us that establishments, as much as fringes, have their id). “This is our due” joined “Reagan proved deficits don’t matter” and “Fuck yourself” in summing up the mood after the Republican sweep in the midterms of 2002. (The last of these was voiced in 2004, but the spirit was enduring.)

I start with this digression in order to set the stage for understanding the massive package of tax cuts that’s soon going to hit Donald Trump’s desk for signing. It’d be foolish to call every provision in the bill bad—phasing out the mortgage-interest deduction for people who are rich enough to shoulder mortgage debts of over $1 million won’t get much resistance outside of Manhattan and the Bay area—but overall this is a budget-blowing joke of a bill being rushed through with a farce of a process. Some observers are bewildered. But if you operate with the theory that the central goal for the establishment G.O.P., its reason for arising from slumber, is to reduce taxes, then any bewilderment you might feel over its turns and pivots and contradictions is dispelled.

Now we get to the main point, which is that passage of this bill marks the end of Trump’s presidency. Trump (along with his supporters) seems to feel that triumphing on taxes will give him the momentum to move onto other great things. It won’t. It will offer Republicans the chance to abandon him. More than anything, this piece of legislation is what Republicans needed from the president. Trump has been a building fire that Republicans wouldn’t put out because they needed it to light their cigars. But now the G.O.P. has got what it wanted. It can puff and move along.

Trump might think what comes next is his wall or maybe even—who knows how much he dreams?—an infrastructure bill. These won’t happen. His leverage with his party will be spent. Even minor reforms to immigration policy are unlikely to happen. Trump is reportedly set to appoint Tom Cotton, the lone immigration wonk among Republicans in the Senate, to the C.I.A., where Cotton will abandon domestic legislation in favor of foreign-threat assessments. With his reputation for hawkishness, Cotton will, as the joke goes, fill a much-needed void.

With Senate Majority Leader Mitch McConnell, nothing is brash or loud. He won’t denounce Trump in fiery orations. We’ll just notice that Trump’s enemies seem to be having easier time circling in on him. The car that was parked in the path of the fire truck yesterday will have moved mysteriously to the side. McConnell will clear his throat and look the other way as Trump’s foes charge through. Trump might have no choice but to push through this bill, and he no doubt likes what it does. But tax cuts were also Trump’s bargaining chip in dealing with the G.O.P. He’s about to let that chip go, just as the G.O.P. is about to let Trump go.