(CNN) President Donald Trump and Democratic White House hopefuls have plunged into a new battle over Justice Brett Kavanaugh because they have strong incentives to put the Supreme Court at the epicenter of the election.

A number of 2020 candidates demanded Kavanaugh's impeachment after the New York Times published excerpts of a new book containing details about sexual misconduct allegations that he has previously denied, but that revived the raw emotions spurred by his fight for confirmation last year.

"Brett Kavanaugh lied to the U.S. Senate and most importantly to the American people," California Sen. Kamala Harris wrote Sunday morning on Twitter. "He was put on the Court through a sham process and his place on the Court is an insult to the pursuit of truth and justice."

The Democratic front-runner, Joe Biden, stopped short Sunday evening of calling for impeachment but raised concerns about the integrity of Kavanaugh's confirmation process.

Trump barged into the fray in Kavanaugh's defense, relishing the opening to revive one of the most emotional and GOP-unifying chapters of his presidency.

"Brett Kavanaugh should start suing people for libel, or the Justice Department should come to his rescue. The lies being told about him are unbelievable," Trump tweeted Sunday morning.

The eagerness of both sides to engage reflects the confrontation's potential to fire up base activists and an understanding that the fate of the Supreme Court has rarely been more important to the outcome of political and culture wars following signature decisions on the 2000 election, campaign finance, same sex marriage, abortion and health care.

The reports are reviving the pitched political exchanges that threatened Kavanaugh's confirmation, most notably over allegations by Christine Blasey Ford that he assaulted her when he was drunk at a party when both were teenagers. Kavanaugh vehemently denied the claims.

New scrutiny on confirmation process

Two Times reporters who wrote the book said they corroborated a prior claim of sexual misconduct against Kavanaugh. They also concluded the FBI interviewed none of the potential witnesses, throwing new scrutiny on White House officials and Republicans who strong armed his confirmation last year.

The book also contains a former male classmate's new allegation that the authors say was corroborated by two sources. The authors reported the former classmate came forward to the FBI and senators concerning an incident he witnessed and said the FBI did not investigate the claim.

The New York Times Sunday evening published an Editor's Note saying the female victim declined to be interviewed and friends say she does not recall the incident.

A person close to Kavanaugh told CNN the accusation isn't new because, according to the book's authors, it had been reported to the FBI and some on Capitol Hill. This person said, citing the new book, that some Democratic senators, despite having been told of the allegations before Kavanaugh was confirmed, did not act.

CNN is not reporting any details related to the allegation because it has not independently verified it.

A Supreme Court spokeswoman said Kavanaugh had no comment on the new allegation against the justice or the calls for impeachment.

'This is the game they play'

Far from playing down the fresh controversy to allow Kavanaugh to quietly repair his reputation and embark quietly on his lifetime appointment to the Court, Trump escalated it.

The President must supercharge GOP turnout to win in 2020 , so is happy to exploit the latest Kavanaugh controversy to remind his base of one of his key achievements, the installation of a conservative majority on the Supreme Court against fierce liberal opposition.

The clash plays into his desire to frame Democrats as entrapped by radicals who want to march the country left and who he claims are smearing the reputation of an innocent man in their desperation to thwart conservative goals. Trump also is keen to position himself as a bulwark against Democratic hopes of reshaping the Court in order to appeal to crucial evangelical voters.

"Can't let Brett Kavanaugh give Radical Left Democrat (Liberal Plus) Opinions based on threats of Impeaching him over made up stories (sound familiar?), false allegations, and lies.

"This is the game they play. Fake and Corrupt News is working overtime! #ProtectKavanaugh" Trump tweeted.

Can't let Brett Kavanaugh give Radical Left Democrat (Liberal Plus) Opinions based on threats of Impeaching him over made up stories (sound familiar?), false allegations, and lies. This is the game they play. Fake and Corrupt News is working overtime! #ProtectKavanaugh — Donald J. Trump (@realDonaldTrump) September 15, 2019

A new skirmish over a potent base politics issue comes at an ideal moment for Trump, whose approval rating has recently dipped below 40% — a danger sign ahead of a reelection bid.

Trump demanded that his Justice Department "rescue" Kavanaugh, and advised the judge to sue over the book. He also accused Democrats of trying to influence the rulings of the newest justice, an ironic comment given his own relentless habit of publicly attacking judges and complaining about their verdicts.

His remark about the Justice Department also calls to mind previous occasions when the President has appeared to seek to leverage its power to counter political opponents.

Trump's foes were already up in arms over the department's role in the Kavanaugh drama after it emerged Friday that Attorney General William Barr plans to confer a distinguished service award on the department team that worked on the nomination.

Reflecting the unifying nature of Supreme Court controversies, Mitch McConnell also came to Kavanaugh's defense on Sunday. The Senate Majority leader's expert and controversial handling of nominations to the top bench has done more than any other single factor to enshrine a conservative majority.

"The far left's willingness to seize on completely uncorroborated and unsubstantiated allegations during last year's confirmation process was a dark and embarrassing chapter for the Senate," the Kentucky Republican wrote on Twitter.

"Fortunately a majority of Senators and the American people rallied behind timeless principles such as due process and the presumption of innocence. I look forward to many years of service to come from Justice Kavanaugh."

Democrats playing catch-up over Supreme Court politics

Kavanaugh's confirmation was especially inflammatory because it took place against a backdrop of the #MeToo movement that fundamentally altered the attention society paid to decades of sexual harassment allegations made by women in show business, politics, journalism, the media and the corporate world.

Combined with anger over the defeat of Hillary Clinton in 2016 and allegations of sexual misconduct against Trump — which he has denied — the Kavanaugh saga electrified the liberal base but also a wider cohort of women voters who will be pivotal in 2020.

While Republicans have used the Supreme Court as a campaign trail rallying cry for years, Democrats have been slower to exploit what has become a pivotal societal question.

But the aggressive response to the new Kavanaugh allegations demonstrates that the left is now just as motivated by the Supreme Court as conservative voters.

As the New York Times report broke Saturday night, Democratic candidate Julián Castro tweeted that it was clearer than ever that Kavanaugh "lied under oath. He should be impeached."

The former Housing and Urban Development Secretary called on Congress to review the "failure" of the Justice Department to properly investigate allegations against Kavanaugh.

Sen. Elizabeth Warren of Massachusetts, Sen. Bernie Sanders of Vermont, former Texas Rep Beto O'Rourke and South Bend, Indiana, Mayor Pete Buttigieg all called for Kavanaugh's impeachment.

Later Sunday, Harris urged supporters to sign a petition calling for Kavanaugh's impeachment. Warren complained that Kavanaugh's confirmation was pushed through the Senate without a full investigation of allegations against him.

"Confirmation is not exoneration, and these newest revelations are disturbing. Like the man who appointed him, Kavanaugh should be impeached," she tweeted.

Biden did not call for impeachment but said in a statement that the New York Times story raised "profoundly troubling questions about the integrity of the confirmation process that put Brett Kavanaugh on the Supreme Court in the first place."

And the former vice president, who has been criticized in this campaign for his handling in 1991 as Senate Judiciary Committee chairman of confirmation hearings in which Anita Hill raised sexual harassment allegations against Clarence Thomas, said women who raise allegations against powerful men need to be heard.

"It takes enormous courage for a woman to come forward, under the bright lights of millions of people watching, and relive a traumatic memory," he said.

In practice, there is a minuscule chance that Kavanaugh would be convicted of any impeachment charges brought by the Democratic House, given the need for a two-thirds majority in the Republican-held Senate.