In his “Confessions,” Saint ­Augustine admitted he had prayed, “Lord, make me chaste, but not yet.” Sen. Elizabeth Warren would understand.

She wants to be the Democrats’ 2020 nominee, but doesn’t necessarily want to be the front-runner, at least not yet. She’d rather watch Joe Biden have the honor — and the target on his back.

Biden will once again be the ­piñata at Thursday’s debate because the best way for any of his nine rivals to gain ground is to beat up on him, as Sen. Kamala Harris proved in the first debate.

But Warren is the one to watch this time. Most national polls have her second, with two recent ones showing her trailing the former vice president by just four points.

She is drawing by far the largest crowds and is focused, energized and organized. Biden, on the other hand, had a terrible week, with a growing realization in the party that his flubs and memory lapses are not passing problems.

Both his blood-filled eye and his gibberish remarks about climate change added to doubts he can go the distance. His team wants to cut back on his schedule and lowered expectations for Iowa and New Hampshire, moves that smell like panic.

The only surprise to me is that the cracks in his game are so obvious just four months after he entered. I assumed the aura of inevitability that greeted Biden’s candidacy would carry him through this year, with the left-wing media glossing over his problems in their desire to defeat President Trump.

But Biden’s weaknesses are so blatant that the party’s top propaganda outlets, The New York Times and The Washington Post, gave front-page play to critical articles. That amounts to a five-alarm fire.

Most surprising, David Axelrod, the 2008-campaign guru who helped put Barack Obama and Biden into the White House, has become a fierce critic of Biden.

“It’s one thing to have a well-earned rep for goofy, harmless gaffes. It’s another if you serially distort your own record. @JoeBiden is in danger of creating a more damaging meme,” Axelrod tweeted Friday. He was reacting to a Biden claim that he never favored the Iraq war, even though he voted to give President George W. Bush authority for the 2003 invasion and turned against it only when the war went south.

Now that more voters will be paying more attention, Biden likely will pay a bigger price for poor performances. And because Warren is a much better debater than he is, and because others also will be gunning for him, don’t be shocked if Thursday’s showdown upends the race and she soon emerges as the front-runner.

At which point, Dems will have a new problem: The whiff of anti-Americanism in many of the candidates’ policies will become more pronounced without Biden at the top. Warren and Sen. Bernie Sanders are especially guilty of making sweeping condemnations of the shape and structure of contemporary society.

Indeed, they and their fellow candidates want such radical changes that it’s hard to figure out what, if anything, they like about America.

A little background. After Trump’s election, Washington Dems started with the resistance, then morphed into a soft secessionism, with some boycotting Trump’s inauguration and State of the Union speeches.

Since they took the House in 2018, a growing list of members declared their intent to impeach the president even though they have not identified clear offenses. Although special counsel Robert Mueller suggested no charges, many Dems refuse to accept Trump as the legitimate president.

Still, these departures from political norms largely reflected a blind hatred for one man. As destructive as that is, something different — and worse — is happening now.

The 2020 candidates and their supporters appear to be as angry at America as they are at Trump. They express contempt for our history and act as if everything about our country is so polluted that we must smash the existing order and start over.

As a result, nearly all the candidates are espousing ideas that are so far out of the mainstream that they sound more like calls for ­revolution than reform.

Abolish the Electoral College is one example, pack the Supreme Court is another. Opening the borders and giving free health care to illegal immigrants, ideas that were fringe four years ago, are now ­basic requirements for all Dems.

Other bizarre policies include Medicare for All, the Green New Deal, wealth taxes and reparations for the descendants of slaves. Each has found support.

The impact of these plans would be profound, both in price and how they would change the way millions upon millions of Americans live and work.

Consider that Medicare for All would outlaw private insurance plans that now cover about 150 million people, most of them job-related. Both Warren and Sanders support the idea, and several others say that a single-payer government system is the ultimate goal.

Sanders said his plan would cost between $30 and $40 trillion over a decade, though he argues poor families could save over current costs.

Biden, by comparison, rejects the notion of a health-care reboot, saying fixing ObamaCare would be better and cheaper.

Similarly, the Green New Deal aims to radically transform the nation’s energy landscape by retrofitting every building to meet draconian standards. The apocalyptic language comes with a matching price tag of up to $93 trillion over a decade, or more than $600,000 per household, according to one estimate.

Sanders, Harris and Beto O’Rourke all subscribe to the hysteria, while Warren offers her own plan to spend $2 trillion over 10 years to create a green industrial policy.

“The climate crisis is the existential crisis for our world,” Warren said during CNN’s seven-hour slog on the issue. She believes “we have 11 years” to cut emissions in half and supports a ban on natural gas fracking. She also wants to phase out nuclear energy, which supplies 20 percent of the country’s electricity.

Yet Warren saves her greatest zealotry for a war on corporations. For starters, she wants to raise their taxes, let employees pick 40 percent of directors, restrict executives’ pay and give Washington more power by requiring a federal charter. She says all this despite the fact that an estimated 50 million people work for large corporations.

In short, she doesn’t just want Trump’s job. She wants the power to transform American life in ways that could be the death knell for millions of other people’s jobs, too.

Betraying the blue

Retired NYPD Sgt. James Burke calls the firing of Police Officer Daniel Pantaleo “craven” and writes:

“The only thing even close to this betrayal was when Officer Phillip Cardillo was assassinated in 1972 and Mayor Lindsay and Commissioner Patrick Murphy allowed his assassins to escape.”

Raising taxes like a robot

Mayor de Blasio’s call for a robot tax sounds creative — until you remember who he is and what he does. Raising taxes is always his first instinct, so why should robots be different?