WASHINGTON — In an abrupt about-face, Hillary Clinton said Tuesday night that she would endorse her 2016 rival Bernie Sanders if he won the Democratic nomination to face President Trump in November.

The former secretary of state had earlier refused to say whether she would endorse Sanders in an interview with The Hollywood Reporter published Tuesday, instead telling the outlet: “I’m not going to go there yet.” She had also offered a broad condemnation of the progressive candidate’s style of politics.

“I thought everyone wanted my authentic, unvarnished views!” Clinton tweeted Tuesday night. “But, to be serious, the number one priority for our country and world is retiring Trump, and, as I always have, I will do whatever I can to support our nominee.”

Her initial comments ripped open the scars of the brutal 2016 primary battle between Sanders and Clinton just as Democrats are poised to begin voting on their next nominee. Sanders’ loyalists believed the Democratic establishment had rigged the primary in favor of Clinton, who won the nomination but ended up losing the general election to Trump.

For her part, Clinton wrote in her memoir “What Happened” after her 2016 defeat that she felt some of Sanders’ criticism of her had helped propel Trump to victory, and she begrudged Sanders for not backing her campaign quickly enough after she sewed up the nomination. In The Hollywood Reporter interview, she accused Sanders of fostering a toxic culture in his campaign.

“We’re still in a very vigorous primary season. I will say, however, that it’s not only him, it’s the culture around him. It’s his leadership team,” Clinton had said. Then, referring to a cadre of aggressive, online Sanders backers, she continued: “It’s his prominent supporters. It’s his online Bernie Bros and their relentless attacks on lots of his competitors, particularly the women.”

She added in the interview: “I really hope people are paying attention to that because it should be worrisome that he has permitted this culture — not only permitted, (he) seems to really be very much supporting it.”

Sanders, like other senators who are running for president, was in Washington on Tuesday to participate in President Donald Trump’s impeachment trial. He refused to comment on Clinton’s critical comments, saying only in a statement, “ Together, we are going to go forward and defeat the most dangerous president in American history.”

Even before Clinton’s evening tweet, her aides had sought to minimize any fallout from her comments. Nick Merrill, Clinton’s spokesman, tweeted that “we all need to work our heart out for the nominee, whoever that is, and @HillaryClinton, as usual, won’t be any exception.”

Still, the lingering tension between Clinton and Sanders is evident. In the interview, Clinton was asked about comments she makes in an upcoming documentary in which she says Sanders has been in Congress for years but “nobody likes him, nobody wants to work with him, he got nothing done.”

Asked if that assessment still holds, she said “yes.”

Clinton’s accusations that Sanders fostered a culture of sexism in politics are especially sensitive now given that Sanders’ top progressive rival in the 2020 race, Warren, has accused him of privately telling her a woman couldn’t win the White House.

Sanders has denied that, but Warren refused to shake his outstretched hand after a debate last week in Iowa and both candidates accused the other of calling them “a liar.” Warren has steadfastly declined to comment further, but the 78-year-old Sanders said Sunday that while sexism was a problem for candidates, so were other factors, like advanced age — touching off another round of controversy.

Clinton said, “I don’t think we want to go down that road again where you campaign by insult and attack and maybe you try to get some distance from it, but you either don’t know what your campaign and supporters are doing or you’re just giving them a wink.”

“I think that that’s a pattern that people should take into account when they make their decisions,” she said.

His feud with Warren has overshadowed a series of clashes between Sanders and another 2020 rival, Biden, for an op-ed penned by one of the senator’s supporters suggesting that the former vice president was corrupt.

“It is absolutely not my view that Joe is corrupt in any way. And I’m sorry that that op-ed appeared,” Sanders told CBS.

The op-ed, published in “The Guardian” newspaper by Fordham University law professor Zephyr Teachout, claims Biden “has perfected the art of taking big contributions, then representing his corporate donors at the cost of middle- and working-class Americans.”