So tell me, Mitch, in these, your final hours as Senate majority leader: Were the judges and the tax cuts worth it?

Were they worth the sacking of the Capitol? The annexation of the Republican Party by the paranoiacs and the delusional? The degradation, possibly irremediable, of democracy itself?

Those close to him say that Mitch McConnell has his eye on his legacy, now more than ever. But I wonder whether he already understands, in some back bay of his brain where the gears haven’t been ground to nubs, that history will not treat him well.

McConnell may think that the speech he gave on the Senate floor on Jan. 6, objecting to the election deniers, will spare him history’s judgment. It will not. It did not make him a hero. It simply made him a responsible citizen.

If McConnell ultimately votes to convict Donald Trump in his second Senate impeachment trial — he has suggested he’s open to the idea — that won’t make him a hero, either. He will simply have done the right thing and likely not for the right reasons: As Alec MacGillis makes plain in his excellent book “The Cynic,” Mitch McConnell never does anything unless it serves the interests of Mitch McConnell.

Which is why McConnell made his unholy alliance with Donald Trump in the first place. By his own admission, McConnell plays “the long game” (it’s the name of his memoir, in fact). He’s methodical in his scheming, awaiting his spoils with the patience of a cat. So if hitching his wagon to a sub-literate mob boss with a fondness for white supremacists and a penchant for conspiracy theories and a sociopath’s smirking disregard for the truth meant getting those tax cuts and those conservative judges … hey, that’s the cost of doing business, right?

Isn’t it?

Well. Live by the mob, die by the mob. That’s what happened on Jan. 6.

What “long game” McConnell had failed to foresee: The problem was coming from inside the House. And the Senate. A quarter of his caucus helped fuel that siege by cynically disputing the results of a fair election. All that staring into the distance came at the expense of McConnell’s peripheral vision. He was now outflanked on his right.

Yet it shouldn’t have come as a surprise. Anyone who’s spent any time watching Republican congressional politics over the last quarter century has witnessed this phenomenon time and time again: A Republican leader, once hailed as a fire-spewing Komodo dragon, suddenly finds himself under attack from even more blistering fire-breathers within his ranks.

It happened to John Boehner, who came of age as an anti-establishment radical but lived out his days as speaker of the House under the implicit and sometimes explicit threat of a party coup. (He resigned his post in 2015 and eventually went into the weed business.) Years earlier, it happened to Bob Dole, who was known early in his Senate career as “Darth Vader” and “Aya-Dole-ah” and ended it as a befuddled majority leader, exasperated by all the proto-Gingriches who’d suddenly appeared in his midst.

For years now, the Republican Party has been radicalizing at a furious rate, moving rightward at a far faster clip than the Democrats have moved to the left. Political scientists even have a term for it: “asymmetrical polarization.” How we got to this frightening pass is complicated, but chief among the reasons is that the G.O.P. has been on a decades-long campaign to delegitimize government. Run against it long enough, and eventually you have a party that wants to burn the system to the ground.

McConnell, now on his seventh term, has been cynical and power-hungry enough to keep up with his party’s rightward lurch at every step.

When Republicans embraced the Southern Strategy, deciding that racial resentment — if not hatred — would power their rocket to the majority? No problem. His dalliance with the civil rights movement was only a youthful fling.

When the Republicans made their pact with social conservatives and evangelicals, realizing that pro-business policies couldn’t capture a majority’s imagination? No problem. He abandoned his support for abortion. (Yes, McConnell was once pro-choice.)

When anti-tax sentiment overtook the party’s desire to contain the deficit? No problem. He loved tax cuts, loved business, loved the rich (read Jane Mayer’s knockout McConnell profile from April for details about all the thumbs he has in moneyed pies).

When preserving power prerogatives overtook his party’s concerns about the former Soviet Union? No problem. McConnell refused to hear out warnings about Russian interference until weeks before the 2016 election (at which point he buried them), and he refused to consider bipartisan legislation that would attempt to curb foreign meddling until he earned himself the moniker “Moscow Mitch.”

When his party went from free trade to nativist populism, powered by xenophobia and racist resentment? Not a problem. He’d side with the populists, including their dangerous Dear Leader, until his workplace was overrun, five people were dead and the Constitution itself was among the critically injured.

It was only a matter of time before members of McConnell’s own caucus began to align themselves with — and inflame — the insurrectionist hordes. They were just doing what McConnell has done his whole political career: lunging at opportunities to serve their own political ends.

“They saw all of this behavior in McConnell,” the political scientist Norman J. Ornstein told me. “The ends-justify-the-means philosophy, the focus on winning over governing, the willingness to blow up every norm in the Senate and the political process.”

The mercenary focus on winning makes McConnell similar to someone else in his party, too: Donald J. Trump.

And power is really all the old-school G.O.P. has to cling to. Its philosophy of sharply limited government and free enterprise has never had enough appeal to win over a true majority. Staying in power required voter suppression, gerrymandering, the Electoral College, oceans of money.

McConnell has worked indefatigably to defend them all — and to make sure the Democratic agenda never succeeds. His dirtiest maneuver was to let a Supreme Court seat sit empty for a year, rather than allow Barack Obama to fill it. But his obstructionist warfare stretches back much further than that. While minority leader, he either threatened or made use of the filibuster at every turn; once he got control of the chamber, he still brought very little legislation to the floor.

And we wonder why voters in 2016 turned to a know-nothing vulgarian who promised to blow the place up.

McConnell is not an enabler. He’s a ringleader, as responsible for the politics of destruction — which has morphed from a metaphorical to a literal description in the last two weeks — as Trump himself.

If McConnell is truly concerned with how history views him, he should spend his waning Senate years actually doing things. Drumming up support to convict a dangerous former president. Allowing popular legislation to come to the floor regardless of which party initiated it or holds the reins. Imagining a world whose borders stretch beyond his brutish, small-minded self.

Being a leader, just once."