For months, Democrats have talked about how cordial their presidential primary contest has been, with candidates exchanging a “welcome to the race” here and a “so glad she’s running” there. Criticisms were done in a read-between-the-lines style, and rarely did the candidates even name the person they were going after.

No longer. The Democratic contest is entering a new phase as candidates shed their reluctance to counter one another, most visibly in a newfound willingness to criticize former vice president Joe Biden, who has jumped to an early lead in the polls.

Their arguments are merging with fresh attacks on Biden by President Trump, as both Democrats and the Republican incumbent share the same goals — to knock the former vice president out of the race — and with a similar undertone: that he’s too old and carries too much baggage.

Trump on Tuesday called Biden “a loser” and reminded listeners that he had earned only 1 percent in the 2008 Iowa caucuses — before, as the president put it, “Obama took him off the trash heap.” Then he sought to raise questions about Biden’s health, much as he did about Hillary Clinton in 2016.

“Now, I have to tell you, he’s a different guy,” Trump said. “He looks different than he used to. He acts different than he used to. He’s even slower than he used to be.”

On Friday, in an interview on Fox & Friends, Trump reiterated his view that Biden “doesn’t have what it takes” to be president. Asked what that meant, he replied, “it means mental capacity.”

The double-teaming offers a preview for the first Democratic debates in two weeks, where much of the focus is expected to be on picking apart Biden’s extensive record.

Beto O’Rourke, the former congressman from Texas, on Thursday launched the most aggressive and wide-ranging attacks on Biden so far, questioning some of his past positions, his more recent statements, and the sincerity of his shift on abortion rights. But he also made the argument that Biden represented the candidate of a prior generation, not the one of the future.

“We cannot return to the past,” he said on MSNBC’s “Morning Joe.” “We cannot simply be about defeating Donald Trump.”

Later in the interview, asked by co-host Willie Geist, “So is Joe Biden the return to the past?” O’Rourke replied, “He is.”

“And that cannot be who we are going forward,” he said. “We’ve got to be bigger; we’ve got to be bolder. We have to set a much higher mark and be relentless in pursuing that.”

The criticism comes a week after the entire Democratic field separated themselves from Biden’s position of supporting the Hyde Amendment, which prohibits using federal money to pay for most abortions. Biden reversed his position after an outcry from women, Democratic activists and other candidates.

Biden — who himself ran for president in 1988 as the generational candidate attempting to counter older politicians who spoke from teleprompters and cue cards — did not respond to the criticism on Thursday. But earlier in the week he answered questions about his age, which Trump raised as they both appeared in Iowa.

“It’s self-evident,” Biden said during an exchange with reporters. “You know it’s a ridiculous assertion on his part. But anyway look it’s a . . . People have a right to question all of our ages. That’s totally legitimate thing. But like I say, watch me. Just watch me.”

He also dismissed questions about voters who want a fresh face, saying, “Vote for a new person then.”

Biden, 76, is three years older than Trump, who turns 73 on Friday. But the age differential is much greater with some of his Democratic rivals. Biden has been in public life for longer than O’Rourke has been alive. He was in his second term as a U.S. senator when South Bend, Ind., Mayor Pete Buttigieg was born.

Buttigieg, like O’Rourke, has repeatedly referred to a need for a new generation of leadership. On Tuesday, in a foreign policy speech, Buttigieg warned Democrats that they must offer voters a vision that does not “turn the clock back to the 1990s.”

“It has been difficult to identify a consistent foreign policy in the Democratic Party,” Buttigieg said of his party over the past two decades, a period of time in which Biden spent eight years as vice president and, before that, served as a key Senate leader on foreign policy issues.

The intra-Democratic criticism came as candidates have gotten more aggressive in trying to define themselves not only by what they want to do — but also by who they are not.

Former Colorado governor John Hickenlooper has sharply criticized Sen. Bernie Sanders (I-Vt.) for his beliefs in democratic socialism. In response, Sanders tweeted video in which Franklin Delano Roosevelt, who shared some of Sanders’s agenda, insisted that “cross our heart and hope to die, we believe in all these things.”

In addition to his dust-up with Hickenlooper, Sanders has criticized Biden for his vote authorizing the Iraq War and his support for various trade agreements, all of which Sanders opposed. Sanders also has started a twitter hashtag #NoMiddleGround, in an attempt to counter Biden’s rhetoric about seeking compromise.

Andrew Yang, a 44-year-old tech entrepreneur running for the Democratic nomination, criticized Biden on Sunday for skipping out on an event in Cedar Rapids, Iowa, that 19 of the 23 candidates attended.

“Joe Biden must really not like to travel,” he joked to some groans at the gathering.

Biden responded later, saying that he had skipped the weekend gathering because Saturday was his daughter’s 38th birthday, while Sunday was his granddaughter’s high school graduation.

“I would skip inauguration for that,” Biden said.

“Out of 19 presidential candidates in Iowa this weekend I guarantee you that several were missing family obligations,” Yang responded on Twitter. “That’s what happens when you run for President. If a front-runner says that we have different values, that’s on him.”

O’Rourke had previously refrained from directly attacking his 2020 competitors and has built his reputation as a sunny campaigner who has vowed he would stick with positivity. Despite advice from some of those around him, he was reluctant to go negative against Sen. Ted Cruz (R-Tex.) during their 2018 Senate race. O’Rourke eventually referred to Cruz by the nickname Trump had given him — “Lyin’ Ted” — during one of their debates, a decision he later said he regretted.

During one of his first campaign events in Iowa, O’Rourke winced when a voter stood and said he wanted “youth” and that he hoped Biden did not get into the presidential contest.

“I have to disagree a bit,” O’Rourke said in March. “I think if Vice President Biden gets into the race, I think we could use his perspective.”

“I can’t tell anyone else what to do,” he said later that day, reflecting on the exchange. “I can only control my own actions. You will not see us demeaning any of the other candidates — ever uttering a personal word about anyone else.”

O’Rourke on Thursday seemed to try to make a harsh critique about Biden’s candidacy without getting too personal. But he was building on the Trump attack from earlier in the week, when the president maligned Biden’s physical state.

O’Rourke then launched into an indictment of several of the policies of the Obama administration, which has also been a rare direct line of attack among Democratic presidential candidates.

Asked what he would tell voters to persuade them to vote for him rather than Biden, O’Rourke replied that “you cannot go back to the end of the Obama administration and think that that’s good enough.”

The country “had real problems before Donald Trump became president,” O’Rourke said, pointing to the wealth disparity between black and white Americans, the persistent problem of gun violence and the Obama administration’s record on border deportations, which he described as “destroying families and breaking up communities.”

Like other Democrats, O’Rourke earlier this month was critical of Biden over his support of the antiabortion Hyde Amendment. When Biden reversed his stance, O’Rourke issued faint praise: “Well, he got to the right place, and . . . yeah, so that’s really all I can say on that,” O’Rourke said last week in an interview with The Washington Post.

By contrast, in Thursday’s “Morning Joe” interview, O’Rourke openly questioned whether Biden’s shift on the Hyde Amendment was genuine.

“Look, you’ve got to ask yourself where Joe Biden is on the issues that are most important to you,” O’Rourke said. “Did he support the war in Iraq that forever destabilized the Middle East? Does he really believe that women of lower income should be able to make their own decisions about their own body and be able to afford health care in order to do that? He supported the Hyde Amendment.”

The Texas Democrat also took aim at Biden’s recent remarks on China.

“He says China is not [a] threat, nothing to worry about,” O’Rourke said. “And now seems to be changing his message on that. So I’m not exactly sure what he believes or what he should apologize for. I only know that this country should be able to do far better.”

Sean Sullivan contributed to this report.