If past is prologue, the losing team in Sunday’s Super Bowl will swallow its bitter disappointment and graciously offer its congratulations to the winners.

Our politics used to be like that.

After Vice President Al Gore lost the 2000 presidential election by a 5-4 vote in the Supreme Court, he expressed his disagreement and frustration, but declared that “partisan rancor must now be put aside.”

“I accept the finality of the outcome,” Gore said in a televised address. “And tonight, for the sake of our unity as a people and the strength of our democracy, I offer my concession.”

He said he had telephoned ­George W. Bush, congratulated him and made a point of calling him “president-elect.”

A humble acceptance of election results has been a hallmark of our republic for more than 200 years and is key to the peaceful transfer of power. Before and after Gore, all those who were defeated licked their wounds in private while publicly bowing to the will of the people.

Except Hillary Clinton. Although she conceded to Donald Trump in November 2016, she soon made it very clear that she did not consider his victory legitimate.

That launched the Russia, Russia, Russia hysteria — and it was highly contagious. Some Democrats began to talk of impeaching Trump before he was inaugurated, and the last three years were defined by endless resistance to his presidency and attempts to drive him from office.

The minute one effort failed, another began. The pressure on Electoral College electors to switch their votes was succeeded by special counsel Robert Mueller, who was succeeded by Ukraine. The allegations changed, but the goal remained the same. And still does.

We can’t be sure what the next front in the war against Trump will be, only that there will be one. Look no further than the Dems’ bitter reaction to their defeat in the impeachment trial to know they still do not accept the results of 2016.

“The Senate turned away from truth and went along with a sham trial,” Minority Leader Chuck Schumer claimed Friday after his push for additional witnesses was defeated. He said Trump’s acquittal, expected to become final Wednesday, would be “meaningless” and “has no value.”

House Speaker Nancy Pelosi, who had boasted that the impeachment she engineered “will last forever,” denied the plain meaning of acquittal. No matter the outcome, Pelosi said, “he will not be acquitted,” adding: “You cannot be acquitted if you don’t have a trial.”

There was a trial, an extensive one, but the fact that Trump won apparently makes it illegitimate. The cancer Clinton started has turned Dems into a party of deniers.

They see fairness only when they win. When they lose, the game was rigged.

Indeed, the impeachers already claim the results of this year’s election can’t be trusted because Trump is a cheater. That was their rationale for wanting to force him from office and off the ballot for the rest of his life.

The impeachment dynamics illustrate how far the disease has spread. Only Dems supported the two House articles, but instead of acknowledging the break with historical precedent, Pelosi and Schumer demonized Republicans as partisan hacks for not supporting them.

This was also the first time impeachment articles did not allege actual crimes, yet it was Republicans who supposedly violated the Constitution. Similarly, Trump’s refusal to comply with subpoenas his lawyers said were invalid proved he sees himself as a monarch.

Those and other juvenile accusations made watching the trial like watching a production of the college cancel culture, where the left, believing itself morally and intellectually superior, aims to silence dissent and invalidate the opposition. The smug and often false assertions of Rep. Adam Schiff suggest he mistook his participation trophies for signs of actual achievement, giving him an inflated sense of entitlement.

The truth for him is anything that makes Trump look bad. ­Everything else is a lie.

This is not to suggest the left’s outrageous behavior is an act. In my experience, the belief in their own virtue is genuine. For the Pelosis, Schumers and Schiffs, it is also a political strategy, but their self-righteousness is sincere.

Which makes it all the more troubling because it means they truly don’t care about the obvious corruption of the Biden family, where son Hunter monetized ­father Joe’s government power.

Nor are they interested in revealing the whole truth about the FBI, CIA and other deep-staters who abused their power to try to tip the 2016 election and undermine a president. As long as a Republican president is the target, and especially when he is named Trump, the more corruption, the better.

So the war goes on. Already the cost to the nation is incalculable, starting with the waste of time, talent and intelligence on the impeachment hearings and trial. The effort was doomed to failure, yet to get there, thousands of government officials, from the president and his team to all of Congress, including lawyers, security, staffers and pages, were sucked into the void, with taxpayers forced to foot an enormous bill.

Far greater is the cost to the national psyche. Political polarization in Washington is tearing America apart, and the bulk of the blame falls squarely on those who refuse to accept Trump as their president.

Until they do, they are the worst kind of losers: sore losers. And they don’t deserve to win a damn thing.

Just more liberal hypocrisy

Two excellent pieces in the Wall Street Journal demand attention. The lead editorial Saturday exposes another example of deception and hypocrisy involving Elizabeth Warren, this time regarding the money she made for years by leasing family land to oil and gas companies. As her political career took off, Warren and husband Bruce Mann quietly sold or transferred mineral-rights royalties to their children.

This matters because Warren promises to ban fracking and condemns fossil fuels in her quest for the presidency. Once again, in her case, “what’s good for me is not for thee.”

The other Journal piece is a Friday op-ed from investor and philanthropist Michael Milken, who alleges the New York Times created a “false narrative” to discredit him and federal opportunity zones.

The headline, “No One is Safe from Biased Reporting,” captures his view of how the Times distorted the facts to fit its anti-business, anti-Trump agenda.

It’s a compelling example of how far the Gray Lady has fallen.

De Blasio ‘left’ himself out yet again!

The assault on the city’s subway and bus system by antifa thugs was disturbing because of the widespread destruction and disruption of Friday commutes.

But nearly as disturbing was the absence of Mayor Bill de Blasio. Top police commanders were forceful in their condemnation, but the mayor was MIA in media accounts.

Then again, his being a no-show isn’t news. That’s who he is and how little he cares.