A nation gawks as Washington sinks deeper into the muck, but put aside your disgust long enough to digest what we’re seeing. Three big things are on display.

First, Democrats are proving again that their force multiplier is a win-or-die zealotry. They were on a mission to kill anybody President Trump chose to replace retiring Supreme Court Justice Anthony Kennedy and, within minutes of Brett Kavanaugh’s nomination, Senate Minority Leader Chuck Schumer announced he would fight Kavanaugh “with everything I have.” All 10 Dems on the Judiciary Committee pledged to vote no.

They looked silly given the nominee’s impeccable credentials, and worse when leftist legal luminaries lined up to praise Kavanaugh as a brilliant jurist and sterling father, husband and mentor.

One feminist supporter of Hillary Clinton called him “a superstar” and urged his confirmation by saying, “He is the most qualified conservative for the job.”

Yet the Dems persisted with unabashed fervor. They tried to stop the hearing before it started, took turns twisting Kavanaugh’s words and insinuated, without evidence, that dark secrets existed.

Orchestrated protests aimed to silence the Senate, an effort that collapsed in farce when Sen. Cory Booker declared he was having his “I am Spartacus” moment. His act of undaunted courage was to release documents that had been approved for release.

Yet all that was mere warmup for the character assassination plot now unfolding. Sen. Dianne Feinstein sat on the allegation of sexual misconduct for nearly two months, only to inject it into the political bloodstream after the final hearing.

Given one last chance for a kill, the assassins are determined not to let their prey escape. Even the Republican concession of a hearing for accuser Christine Blasey Ford to testify isn’t enough. Schumer demands an FBI investigation, which would ensure Kavanaugh couldn’t be confirmed before the midterm elections — and maybe never.

At this moment, Kavanaugh’s confirmation has gone from a slam dunk to a jump ball. That’s because of the second big thing to notice — some Republicans have a streak of French in them and surrendered before the first shots were fired.

With a 51-49 GOP majority, two defectors would kill Kavanaugh, and more than that have announced they have cold feet.

At least three — Jeff Flake of Arizona, Bob Corker of Tennessee and Susan Collins of Maine — are now “maybe” votes. Flake and Corker want to be the new John McCain, meaning they aim to get invited to the liberal Sunday talk shows with the understanding they will criticize other Republicans.

There are no Democrats who play the turncoat role, nor are there any Democrats — not one — who rushed to defend Kavanaugh. Only Republicans waver when the going gets tough, as if a real fight is beneath them.

That is a chief reason why Flake and Corker are “retiring.” Republican voters in their home states of Arizona and Tennessee are sick of them and neither could win a primary let alone a general election. But they appear to be set on one last act of sabotage against Trump and the party.

If that shreds Kavanaugh’s reputation for life and turns the crucial court seat over to a Dem-controlled Senate, what do they care? Their treachery will get them a glowing send-off in the New York Times and maybe some fat lobbying gigs.

Which brings us to the third reason why the kangaroo court is worth watching. It reminds once again why Trump was elected and why his presidency is so important.

Many voters looked at Washington without hope or trust in either party. They saw the Dems as too liberal and willing to stop at nothing to win, the two main legacies of the Obama presidency.

Those voters looked at Republicans with equal disgust for other reasons. They were the errand boys of Wall Street and big business but, even worse, folded like cheap suits on everything they were elected to do.

The relative handful of true conservatives in their midst, the Freedom Caucus, are treated like crazy aunts. The others, like Speaker Paul Ryan, long for the one thing liberals will never give them — respect. And so they ultimately stand for nothing because anything important means they must buck the swamp, which they won’t do.

Trump, to 63 million Americans, was the antidote to both parties. Warts and all, he still is.

He is the fighter Republicans longed for, which is why he still commands upwards of 90 percent of GOP support. They know nobody else would have beaten Clinton, so, without him, one Clinton nominee already would be on the high court and the second one about to join. Neither would be named Neil Gorsuch or Brett Kavanaugh, and you can bet that many Republicans would have played nice and voted yes for her nominees.

Yes, yes, I know, Trump has created many of the dynamics that make him a lone ranger. He doesn’t always return loyalty and trusts no one as much as his own gut. Given his druthers, he would like to govern as a bipartisan president and cut deals like a Lyndon Johnson.

Maybe in the next life. In this one, Trump is the only defense against the left’s smash and smear agenda. It’s either him or the deluge.

Prefer Carmen to ‘Che’ Hey Kid

I’m starting to miss Carmen Fariña.

Because the former schools chancellor was a captive of the unions and the bureaucracy when Mayor Bill de Blasio brought her out of retirement, she could do little good and little harm. Her successor strikes me as capable of great harm.

Richard Carranza is determined to impose a racial quota system on the best schools, without regard to merit. He took his misbegotten campaign to Al Sharpton’s headquarters, where he urged parents to become warriors for change.

“We’re not about improving the system,’’ he declared. “We’re about changing the system.”

There you have it — don’t expect him to fix failing schools, train teachers or do any of the things chancellors normally do.

He’s for revolution and revolution only.

Heaven help the students.

Muppet fairy tale

The Bert-and-Ernie-are-gay story is rocking the media, but color me confused.

The idea of their sexuality makes as much sense as a question readers often ask novelists. What, they demand to know, happens to their favorite characters after the book ends?

Cuomo aide’s gall in the family

It never hurts to try.

Joseph Percoco, former top aide to Gov. Andrew Cuomo, wants a Manhattan judge to let him keep $95,000 of the $321,000 he was convicted of taking in bribes.

Percoco’s lawyers argue that some of the money went to Percoco’s wife for a “low show” job with an energy company seeking state contracts. Since Lisa Percoco did some actual work, they say her family should be able to keep some payments.

Prosecutors have a better argument: The job was part of the bribe, so all the money is dirty.

That’s my ruling. Let’s see what the judge says.