DES MOINES, Iowa (AP) — Democratic presidential candidates have spent weeks reassuring voters they can unify the party, avoid the divisions that plagued the 2016 primary and defeat President Donald Trump in the fall. Instead, the scars of that battle are being ripped open less than two weeks before the Iowa caucuses.

With tensions already escalating between leading Democratic contenders, the party’s last presidential nominee, Hillary Clinton, reignited a years-old feud with Bernie Sanders on Tuesday by refusing to say whether she would support her former rival should he win the nomination this year — before later insisting that she will do “whatever I can” to support the eventual nominee. Clinton also said in an upcoming documentary that “nobody likes” Sanders, adding in an interview with the Hollywood Reporter that he has permitted a culture of “relentless attacks” on his competitors, “particularly the women.”

Clinton’s criticism is the latest — and perhaps, the loudest — flash point in the Democratic Party’s high-stakes nomination fight that has exposed divisions based on gender, race, age and ideology. Democratic officials fear that such divisions could ultimately make it harder to beat Trump, pointing to lingering bad blood between Clinton and Sanders four years ago that may have helped him eke out a victory.

“My No. 1 goal is to win,” Democratic National Committee Chairman Tom Perez told The Associated Press. “The only way this is possible is if we’re united around our eventual nominee, and I have no doubt that every candidate in this race will do that, no matter who she or he is.”

“The stakes get higher on an almost daily basis,” he added, “making it all the more imperative we come together.”

Clarifying her earlier comments, Clinton added later Tuesday in a tweet that “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.”

Trump and his Republican allies, sensing an opportunity to weaken his opponent, have poked at the Democratic infighting from afar in recent days. In particular, the president publicly sided with Sanders in a dispute with Elizabeth Warren and blamed Democrats for treating Sanders unfairly because the Senate impeachment trial prevents him — and three other Democrats seeking the presidency — from campaigning in Iowa.

Trump’s concern, of course, isn’t about the party’s treatment of Sanders. He hopes that continued discord among Democrats might push some disaffected supporters of the Vermont senator in Trump’s direction come November, or at least persuade them to stay home on Election Day.