At a debate in Milwaukee, Democratic presidential candidates Bernie Sanders and Hillary Clinton diverged slightly on how they would reform health care and immigration, while largely agreeing on the need for change in policing. (Sarah Parnass/The Washington Post)

This truly was a PBS debate: genteel, civilized, lacking drama — and full of material that’s already aired somewhere else.

Democratic presidential candidates Bernie Sanders and Hillary Clinton spent most of Thursday night’s debate in what Clinton called “vigorous agreement” — disagreeing only about the methods they’d use to accomplish their common goals.

They both praised President Franklin D. Roosevelt. They both attacked Republican front-runner Donald Trump. They both promised to offer undocumented immigrants a path to citizenship, and to overhaul a criminal-justice system they believe treats blacks and Latinos unfairly.

They both effusively praised President Obama — when Clinton tried to attack Sanders for not being supportive enough of Obama, Sanders praised him more effusively. “Have you ever disagreed with a president? I suspect you may have,” Sanders said, describing his disagreements with Obama as normal behavior between allies.

Democratic presidential candidates Bernie Sanders and Hillary Clinton called for criminal-justice reform for African Americans in policing, jobs and housing during the PBS NewsHour debate on Feb. 11. The debate comes as both candidates try to pitch themselves to black voters. (PBS NewsHour)

Clinton, who has struggled to regain momentum after losing badly to Sanders in the New Hampshire primary Tuesday, sought to cast herself as a more sensible, pragmatic progressive. She also cited her experience as secretary of state, implying that she had a broader array of expertise than Sanders, who focuses largely on economic inequality. “I am not a single-issue candidate, and I do not believe we live in a single-issue country,” Clinton said in her opening statement.

But, as the debate ended, Clinton had done little to establish how her goals were substantively different from those of her opponent. And Sanders responded repeatedly by turning an argument about practical politics into an argument about morality: Asked how he would make a single-payer health-care system work, Sanders pivoted to say that it had to work, because to do otherwise would be unworthy of America.

Sanders cited Roosevelt, whose New Deal programs marked a massive expansion of government safety nets during the Great Depression, as a leader he admired.

“What he did is redefine the role of government,” Sanders said. He paraphrased Roosevelt’s message: “ ‘We are a nation which, if we come together, there is nothing that we cannot accomplish.’ And kind of, that’s what I see our campaign is about right now.”

This might have been a moment where Clinton could have stepped in to draw a contrast between her vision of the change that was needed, and Sanders’s more sweeping vision. Clinton could have said she did not believe the country needed another massive New Deal-style transformation – earlier, she had said that Sanders had been unwilling to “level with” the public about how much his broad plans would cost.

Instead, Clinton simply said she agreed.

“I certainly agree with FDR [being a leader to admire], for all the reasons Senator Sanders said,” Clinton said.

When they did clash, it was largely about issues that were covered in their first one-on-one debate last week.

Sanders, for instance, repeated a criticism he had made in past debates, saying that Clinton had shown her weakness on foreign policy by voting in favor of the Iraq War in 2002. Experience matters, Sanders said – repeating something he’d said in the past. But, he said, “judgment matters as well. Judgment matters as well.”

Clinton responded to that criticism by repeating something she’d said before: that a vote in 2002 was not a plan for taking on the Islamic State in 2016.

They both criticized a surge in deportations of illegal immigrants carried out by the Obama administration, saying they would block the expulsions and offer a new legal path toward citizenship.

“I am against the raids. I am against the kind of inhumane treatment that is now being visited upon families,” said Clinton, who served as Obama’s first secretary of state.

The deportations have begun in recent weeks and affect families who were part of a surge of tens of thousands of Central Americans, many of them minors traveling alone, who flooded across the U.S. border in the past few years. The administration said that all of them had been ordered deported by judges. Latino leaders have criticized the raids, but the administration has said they are necessary to deter others in Central America from making the dangerous journey themselves.

Sanders said he believed that this message was being sent to people who had no other choice. “When we saw children coming from these horrendous, horrendously violent areas,” Sanders said, “I thought it was a good idea to allow those children to stay in this country.” He also said that the country should be welcoming to Latino immigrants: “We have got to stand up to the Trumps of the world who are trying to divide us up.” Billionaire Donald Trump, who won the New Hampshire Republican primary, has called for a massive deportation of all undocumented immigrants.

Most of the night hardly seemed like a debate at all, with both Sanders and Clinton agreeing on a variety of principles. They both called for criminal-justice reform, both called for universal health coverage, and both called for a path to citizenship for undocumented immigrants. “We are in vigorous agreement here,” Clinton said at one point. When they disagreed, it was often about how to accomplish those goals, with Clinton saying that Sanders’s proposals were not achievable and Sanders replying that anything less than his proposals was unworthy of a great country.

Earlier, Clinton was asked about a comment from another former secretary of state – Clinton ally Madeleine Albright.

Albright had told voters in New Hampshire that “there’s a special place in hell” for women who don’t help each other. Young women who support Sanders said this was campaigning by guilt trip.

“She’s been saying that for as long as I’ve known her, for about 25 years,” Clinton said, before moving on to say she hoped men and women felt empowered to choose in this campaign. She finished with a nod to the demographics of the debate stage, where there was one female candidate and two female moderators, PBS’s Gwen Ifill and Judy Woodruff. “This is the first time there’s been a majority of women on the stage. So, you know, we’ll take our progress wherever we can find it.’

Sanders, who is of Jewish heritage and identifies as a “democratic socialist,” said he, too, would make history as president. “Somebody with my background, somebody with my views . . . I think a Sanders victory would be of some historical accomplishment as well,” the senator from Vermont said.

Earlier in the debate, Clinton criticized Sanders for promising sweeping liberal changes that he couldn’t deliver — turning their second one-on-one debate into a circular, rather vague discussion of whose abstract policy proposals were the most achievable.

“I feel like we have to level with people [because] there is a great deal of skepticism about the federal government,” Clinton said. “So we have a special obligation, to make clear what we stand for. Which is why I think we can’t make promises we can’t keep.”

This is an argument that Clinton also directed against Sanders in the last debate, just before the New Hampshire primary. It is a difficult argument to make in a party primary – for one thing, because it essentially tells the party faithful that they can’t have all they want. The other problem is that, in the context of a televised debate, everyone is probably making a few promises they can’t keep. And neither candidate is laying out the nitty-gritty compromises and half-measures that would be essential to actually making law.

Sanders usually turned the questions from the details of his plans to their moral underpinnings, arguing in essence that the United States could do these things because other countries had — and because it would be unjust not to do them.

He finished this section to applause by saying he would make Wall Street bankers pay for major parts of his plans, including an expansion of funding for infrastructure. “We bailed them out. Now it is their time to help the middle class!” Sanders said.

In their opening statements, both candidates tried to pitch themselves to African American voters – a crucial voting bloc in upcoming primaries.

Sanders spoke about what he called a “a broken criminal-justice system,” which he said treats the rich and poor unequally. He said that young people get criminal records for using marijuana, while Wall Street executives escape prosecutions for actions that plunged the country into recession.

Clinton, who earlier in the day received the backing of the political arm of the Congressional Black Caucus, also talked about criminal-justice reform and about fighting discrimination against African Americans in housing and jobs.

Clinton also adopted a refrain from Sanders’s stump speech: “The economy is rigged, in favor of those at the top.” But she returned to a common criticism of Sanders, which is that his plans for expanding government benefits — particularly health insurance — would bring an enormous, and expensive, expansion of government.

“It would probably increase the size of the federal government by about 40 percent,” Clinton said. She focused in particular on Sanders’s promise that his health-care plan could save middle-class families $4,500 per year: “The numbers don’t add up. That’s a promise that cannot be kept.”

Thursday marked the first time the candidates have met since Sanders’s runaway victory in New Hampshire.

The tests of Sanders’s success will come in the next two Democratic contests, held in Nevada on Feb. 20 and in South Carolina on Feb. 27. The most recent polls in South Carolina and Nevada showed Clinton well ahead of Sanders. But they were taken before the results came in from Iowa and New Hampshire.

“If the elections were held today in both those states, we would lose,” Sanders told The Washington Post on Wednesday. “But I think we have momentum, I think we have a shot to win, and if we don’t win, we’ll do a lot better than people think we will.”