LAS VEGAS — Former Housing Secretary Julián Castro insisted that on immigration matters, “there’s no comparison between Obama and Trump, O.K.?”
In response to a reporter’s question, Senator Elizabeth Warren only briefly acknowledged past disagreements with the Obama administration before pivoting to praise former President Barack Obama’s achievements on health care and protecting consumers.
And Representative Seth Moulton of Massachusetts, who didn’t even qualify for this week’s debates, swiped at some of his opponents who made the stage, saying they tried to “tear down the Obama legacy to try and have a viral moment to qualify for the next debate.”
After several of the presidential candidates were critical of some policies overseen by Mr. Obama, who has a 90 percent approval rating among Democrats, at the debates in Detroit, the tone was strikingly different Saturday at the candidates’ first major gathering since then.
Along with courting union members at the forum which drew 19 candidates to the conference of the American Federation of State, County and Municipal Employees in Las Vegas, candidates also made clear that they had no interest in going after Mr. Obama, whether or not they embraced all of his policies.
The result was a gathering that combined all the trappings of a major Democratic cattle call, old-style pro-union Democratic populism and a jolt of shock and sorrow as former Representative Beto O’Rourke found himself trying to make sense of the mass shooting in his hometown of El Paso before leaving to return there.
“There is a lot of injury and suffering in El Paso right now,” Mr. O’Rourke said, his voice cracking. “El Paso is the strongest place in the world. I’m going to be with my family and be with my hometown.”
Former Vice President Joseph R. Biden Jr., who said later in the day that he had tried to reach Mr. O’Rourke, and like many of the candidates would go on to make an emotional appeal for gun control, set the tone for the pro-Obama messaging in his AFSCME appearance Saturday morning.
Mr. Biden, who has a habit of going on tangents and fumbling his lines, gave among the most fluent and forceful remarks of his candidacy as he vigorously defended the Affordable Care Act, Mr. Obama’s signature health care law, and advocated for strengthening it, rather than embracing a new system — like, he implied, Medicare for All.
“We should be building on Obamacare, we should not scrap Obamacare,” he said, rising to his feet as he addressed a cheering crowd.
Mr. Biden, who spoke in glowing terms about the work of public services employees, stressed his longtime commitment to the labor movement.
He also defended the Obama administration’s record on health care and immigration, saying that the administration’s controversial deportation practices focused on “felons.”
[We tracked down the 2020 Democrats and asked them the same set of questions. Watch them answer.]
And he explained his own opposition to decriminalizing illegal border crossings, which is a contrast with several of his more liberal opponents.
“It will be an invitation to come,” he said, going on to add that he and “Barack” sought to increase “the total amount of immigration.”
“We can absorb a lot more people, but there has to be an orderly process to do it,” he said.“Not one that’s going to just invite people to move ahead of the line, unless they’re seeking asylum.”
But, in a departure from remarks he made at a news conference earlier in the week, Mr. Biden refrained from arguing directly that his opponents had been overly critical of Mr. Obama at the last debate.
“Obama remains almost universally popular with Democrats, so it makes sense for Biden to position attacks on his support for Obama’s policies as attacks against Obama himself,” said David Axelrod, Mr. Obama’s former chief strategist. “That said, you can overdo it and appear to be using Obama too much as a shield. And if you take this path, it’s risky to cherry-pick and imply that you privately dissented on some of the more controversial policies while you embrace other, more popular policies as your own.”
Mr. Biden on Saturday morning addressed criticism that he had been selective about which elements of Mr. Obama’s legacy he embraced.
“I’m not cherry-picking anything,” he said as he detailed the economic and international challenges the Obama administration initially faced. “As someone once said before, I’ll take all the blame if I get half the credit.”
He was one of many presidential contenders to lay out campaign promises on issues ranging from labor to health care to immigration as they sought to court union members, a crucial constituency in this state and in the Democratic Party.
Ms. Warren, an advocate for “Medicare for all,” a sweeping single-payer health care proposal, stressed that she would include union leaders in planning a transition to that system, amid arguments from some that many workers like the health insurance plans that are tied to their employers or unions.
“The first part of the transition as I see it is the unions are at the table,” the senator from Massachusetts said. “Nobody does anything without working people well-represented. There are a lot of folks —— you bet,” she said, nodding to applause, “who are in a lot of different positions in terms of health care plans. And what matters most is we get everybody at the table to figure out how everybody gets fully compensated for what they’ve negotiated for. This is a matter of both respect and a matter of economics.”
Asked if she would pledge to have a labor leader as her labor secretary, she exclaimed, “That’s what I want!”
Senator Bernie Sanders did not commit to hiring a union leader as labor secretary, but said he would hire the best person for the job. The crowd did not seem pleased, and Mr. Sanders stood up abruptly.
“I think on my feet, not on my backside,” he said to laughter. “There is no labor secretary stronger in trade and labor than who I will appoint.”