We are living through the early stages of the breakup of the Republican Party.

Yes, the GOP holds tremendous political power, including the presidency and majorities in both houses of Congress (not to mention a majority of the nation's governorships and state houses). But the announcement of a tentative deal between President Trump and the Democratic congressional and Senate leadership (House Minority Leader Nancy Pelosi and Senate Minority Leader Chuck Schumer) to allow the so-called "DREAMers" to remain in the United States, despite Trump's promise during the presidential campaign to deport these illegal immigrants who were brought to the U.S. as children, is the clearest and most dramatic indication yet that the Republican Party has become too incoherent and unstable to govern. The shockwaves radiating out from this latest shift could well shatter the party altogether.

During 2016 GOP primaries, Trump was a master of exposing the barely concealed contradictions that run through the heart of the post-Reagan Republican Party. At the level of rhetoric, Republican candidates and politicians, egged on by Fox News and talk radio, have talked more and more like cultural populists, but they have consistently governed like plutocrats. Trump amped up the populism to unheard of heights — and he promised to act on it.

For Republican loyalists who voted for him in the general election mainly as an expression of opposition to Hillary Clinton and the Democrats, this probably didn't matter much. (Trump's ferocious support for repealing ObamaCare and cutting taxes convinced them that he was on their side, despite his unorthodox positions on other issues and flagrantly unconservative behavior.) But for Trump's most passionate supporters, the nastiness, the threats, and the promises of outright cruelty were the whole point. And no issue telegraphed this longing to lash out like immigration.

We saw glimpses of this tendency emerging from the GOP base way back during the early 2012 primary debates, when audience members cheered Wolf Blitzer's question about whether a hypothetical cancer patient without health insurance should be allowed to die. We heard it again a few weeks later when the crowd at another debate booed a question posed by a gay soldier serving an Iraq. Mitt Romney tried awkwardly to ride that wave of malice by suggesting that immigrants living in the U.S. illegally ought to "self-deport."

It took four years for a candidate to embrace outright callousness, unapologetically encourage it, and even push it several steps further. Trump would build a wall across the southern border to keep out undesired immigrants, make Mexico pay for it, and then round up and deport the undocumented, including the DREAMers who President Obama had acted (with questionable constitutionality) to protect. Conservative voters loved it! By October 2016, 79 percent of Trump supporters favored building the wall. (That compared to 38 percent of all registered voters — which just so happens to be Trump's current approval rating — and 10 percent of Clinton supporters.)

Never Trump Republicans can gloat all they want about the inevitability of the president betraying his base on this issue. That he's apparently done so by way of reaching a deal with the leadership of the Democratic Party only makes it more satisfying for those longing to cry "I told you so!" But that reaction, however understandable, fails to grasp the gravity of what appears to be happening. If Trump really does strike what amounts to an amnesty deal with Chuck Schumer and Nancy Pelosi — a deal that replaces The Wall with "renovation of old and existing fences and walls" — the Republican Party is going to have a revolution on its hands.

That Trump would be willing to betray his base is not, in itself, shocking. (The man's track record shows a willingness to betray anyone and everyone.) But what is shocking is that he could tweet the following in defense of his tentative DACA deal: "Does anybody really want to throw out good, educated, and accomplished young people who have jobs, some serving in the military?" Of course the answer to this question is: Yes, millions of people who voted for you want to do precisely this.

Now, some will undoubtedly go along with this clumsily executed quadruple backflip on the key policy commitment of Trump's presidential campaign. These are the voters who are true-believing members of the Trump cult of personality, for whom literally nothing he does one way or the other matters. But I suspect there are fewer of these people than one might think. Maybe Trump could have kept most of his supporters after shooting someone in the middle of Fifth Avenue — but that was when they assumed he had their backs on immigration. (Killing someone in cold blood might be bad, but it's nothing compared to allowing hundreds of thousands of mostly Mexican immigrants to stay in the country indefinitely.)

If the members of Trump's base do finally turn on him, where are they going to go? Into the arms of pro-immigration Paul Ryan and whatever candidate the still-reigning GOP establishment puts up in 2020? Or will they instead stew through what remains of the Trump presidency (including the now much-more-likely Trump impeachment) while they await a more competent and ideologically coherent candidate to emerge from the fully energized Breitbart/Bannonite wing of the party?

I'd place my bets on the latter. Which doesn't mean that such a hard-right nationalist "workers party" candidate would automatically win the GOP nomination. But it does mean that the 2020 primaries would be a contest over which faction gets to call itself the Republican Party and which ends up forced into the third-party wilderness.

And that, ladies and gentlemen, is a broken party.

Democrats may be inclined to cheer the impending breakup of their electoral rivals, assuming it will put them on a glide-path to victory. But with the Democrats moving into their own uncharted territory, several clicks to the left of where the party has been situated since 1972, they'd be foolish to take anything for granted.

Two years ago, lots of smart people dismissed the possibility of Donald Trump rising to the presidency. It would be unwise to presume something just as shocking couldn't happen again, this time with a candidate who rises from the ashes of the GOP — and who really means all the nasty things he says.