Chris Christie was there at the beginning.

I’m talking about the beginning of this trend among politicians of both parties to demand not just defeat but prosecution of their political enemies.

That occurred at the 2016 Republican National Convention, when Christie made a speech endorsing the party’s presidential nominee, Donald Trump.

At the time, Trump was considered a long shot to win the presidency. But his backers were determined to enjoy the moment.

So they joined in as Christie, a former U.S. Attorney, presided over a sort of mock trial of Democratic nominee Hillary Clinton.

At the end of each allegation, Christie would intone “Guilty or not guilty?”

“Guilty!” the crowd responded to the first few charges.

But then, without any urging Christie, the crowd began spontaneously chanting “Lock Her Up! Lock Her Up!”

At that point, our former governor might have taken the time to remind the crowd that a trial is the necessary prelude to imprisonment.

But he went along in what I’m sure was a spirit of good, clean fun.

Then something unexpected happened:

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Trump won the presidency.

At that point, Trump could have appointed an aggressive Attorney General like Christie, one who would go after Clinton for various charges stemming from the use of a private email server for government documents.

But Trump, who was then a political neophyte, instead named Alabama Senator Jeff Sessions as Attorney General.

Instead of pursuing The Donald’s enemies, Sessions recused himself from what became the Russiagate probe.

That investigation made “collusion” a household word – but only because no such collusion was proven after two years of investigation.

But that was just the beginning.

Once Trump was out of office, he was subjected to prosecution on federal, state and local charges.

Some of the charges may have been substantive. But I suspect that 100 years from now, historians will still be discussing the role of porn star Stormy Daniels in Trump’s prosecution.

Maybe one of them will come up with a good reason the one-time most powerful politician on the planet was prosecuted for a tryst that happened 18 years earlier.

I certainly can’t.

But I think I can safely predict that if he is elected in November, Trump will choose an AG who goes after his political enemies the way they went after him.

We saw the seeds for that planted last week when a coalition of House committees issued a report accusing President Biden of trying to cash in on his office.

“Overwhelming evidence demonstrates that President Biden participated in a conspiracy to monetize his office of public trust to enrich his family,” the committees concluded.

Well, if you can prosecute an ex-president for paying off a porn star, then you can certainly prosecute an ex-president for monetizing his office.

Don’t have evidence? Put enough investigators on it and you’ll find lots of things that make for salacious headlines –if not for a conviction.

I hear a lot of people these days talking about Trump being a threat to democracy. But the real threat is this endless cycle of vengeance on both sides, says Andrew Napolitano.

Napolitano, a former Superior Court judge who’s now the Newsmax legal analyst, said he hopes that if elected, Trump will avoid the temptation to seek revenge.

“Renegade prosecution could be terrible if he did it,” he said of Trump.

“The dirty little secret in American law enforcement is who they decide to go after,” Napolitano added.

Once a target is chosen, the meter starts running. A defendant’s legal fee can go into the millions even if he’s not convicted.

That cuts both ways, however. If not for the controversy over Joe Biden, I doubt we ever would have heard of the gun possession and tax-evasion charges that led to Hunter Biden’s legal woes.

This is a downward spiral, Napolitano said.

“Somebody’s got to break the cycle,” he said. “Otherwise we’re a banana republic.” True enough.

Some members of the crowd at the Democratic National Convention last week were chanting “Lock him up!” In reference to the Donald.

These guys like to talk about achieving a ceasefire in the Mideast.

But they might want to try declaring a ceasefire in Washington first.