It was a battle for the ages. Two of the top campaign consultants in America were going toe-to-toe right here in New Jersey in 1993, when there were few other races to compete for national attention.

In the Democrats’ corner, heading the campaign of incumbent Gov. Jim Florio, was James Carville, a Louisianan who relished comparisons to a bayou alligator.

On the Republican side, representing challenger Christie Whitman, was Ed Rollins, an ex-boxer who loved to mix it up in the political arena.

It was a seesaw battle, but a late surge put Whitman over the top.

In his book “Bare Knuckles and Back Rooms,” Rollins recalls what happened a few days later when he spoke at a post-mortem before an audience packed with Washington journalists.

“I delivered a stream of consciousness dissertation about some of the key reasons for our success, especially Christie’s surprising strength among African-American voters,” he wrote in his book.

Among the reasons was “somewhere in the neighborhood of half a million dollars” in “walking around money” that the campaign had distributed to black ministers.

Rollins writes of how the next day, “I found out my Voicemail had blown a gasket.” He writes of how he realized his big mouth had led him to utter one of the great gaffes in political history. (When it comes to gaffes, Whitman was no slacker herself.)

“Politically, it was really stupid to raise the subject in the first place,” he wrote.

Yes it was – sort of like Joe Biden and his appearance before the Council on Foreign Relations last year.

Biden – who is a virtual gaffe machine – should have kept his big mouth shut about how he used the threat of withholding a billion-dollar loan guarantee to get the Ukrainian government to fire that country’s prosecutor in 2015.

Instead the video shows him going into his own-stream-of-consciousness routine about how he dealt with Ukrainian officials, culminating in this off-the-cuff remark:

“I looked at them and said, ‘I’m leaving in six hours.’ If the prosecutor is not fired, you’re not getting the money.

“Well, son of a bitch, he got fired.”

That declaration was delivered in a joking tone. But the joke turned out to be on Biden.

That gaffe was a major factor in bringing to light the $50,000-a-month position that his son Hunter had with a Ukrainian gas company, even though he had no expertise in the field.

The minority Republicans in the impeachment hearings have made it clear that they intend to call Hunter Biden to the stand so they can grill him on just how he managed to land that plum job in a country where his father the vice president was taking a major role.

As for Joe Biden, he has maintained that he learned of Hunter’s new job only when he read it in the papers.

Perhaps so. But when Hunter Biden was asked in a recent TV interview whether he would have been asked to be on the board of the Burisma gas company if his name was not Biden, Hunter replied “probably not.”

He added, “I don’t think there’s a lot of things that would have happened in my life if my last name wasn’t Biden.”

The Republicans don’t have the votes to compel Hunter’s testimony in the House impeachment hearings. But assuming the Democrats decide to send the case to the Senate, the GOP could put the younger Biden on the stand for as long as they want.

If they’re not satisfied with his answers then they could call on his father to clear things up.

Whether that will happen is anybody’s guess. But the Democrats’ insistence that President Trump was engaged in a quid pro quo regarding Ukraine opens the doors for the Republicans to question whether Biden’s son was engaged in what you might call a “kid pro quo.”

The last thing candidate Biden needs is to be dogged by that issue right up until the Democratic nominating process begins in early February.

He started this race as the consensus nominee, the guy who lines up best against Trump.

But now he’s just part of the pack.

He’s dropped to third in polls for the first nominating battle, the Iowa caucuses behind Massachusetts Senator Elizabeth Warren and South Bend Mayor Pete Buttigieg.

In New Hampshire, he’s tied with Warren, but she has a big home-court advantage there.

Meanwhile Biden’s fund-raising has stalled.

They say money is the mother’s milk of politics.

They also say silence is golden.

Biden should have put the two together.

ADD - BIDEN’S BIG GAFFE: