They agreed that Donald Trump should be impeached, and then they went to war with one another. The fourth of the Democratic presidential primary debates was defined by discord over health care, foreign policy, gun control and much more.

A few notable moment aside, punches were pulled in earlier bouts. Not so much on Tuesday night in Westerville, Ohio, as lightweights swung at established heavyweights, and restraint was less in fashion than before.

Sen. Elizabeth Warren can attest to that fact. While the Massachusetts progressive is not in first place — her surging campaign ranks a comfortable second in the RealClearPolitics polling average with 23.4% support — she was the undisputed target.

A curse but perhaps a sign of front-runner blessings to come, it was Warren against the world for much of the night. Below are the key issues of contention during the three hours of candidate exchanges.

HEALTH CARE

This issue ranks as the most pressing of voter concerns, and Warren was pushed repeatedly to say whether the “Medicare for All” plan she endorses would require an increase in middle-class taxes. Moderators wanted to know. Opponents did too.

“Costs will go up for the wealthy. They will go up for big corporations. And for middle-class families, they will go down,” Warren responded to one pointed question before offering the closest thing to an answer: “I will not sign a bill into law that does not lower costs for middle-class families.”

This was not good enough for fourth-place Pete Buttigieg.

“We heard it tonight, a yes-or-no question that didn't get a yes-or-no answer,” said the mayor of South Bend, Ind. “Look, this is why people here in the Midwest are so frustrated with Washington in general and Capitol Hill in particular.

“Your signature, senator, is to have a plan for everything,” a notably more aggressive Buttigieg continued. “Except this.”

Another Midwesterner took over after that, this time a Senate colleague who polls at just 1.6% in the RCP average: Amy Klobuchar of Minnesota rallied not to Medicare for All, but to expanding Obamacare, turning a Warren complaint into a withering criticism of the former Harvard Law professor.

“And I’m tired of hearing, whenever I say these things, ‘Oh, it’s Republican talking points,’” Klobuchar said, referencing a previous Warren dismissal of questions about increased middle-class taxes. “You are making Republican talking points right now in this room by coming out for a plan that will do that.”

Warren dodged again, responding by telling stories about her time before Washington. The closest thing to her ideological double, Sen. Bernie Sanders, jumped in to remind the audience that he wrote “the damn bill” and to answer directly about the plan Warren has backed:

“At the end of the day, the overwhelming majority of people will save money on their health care bills,” Sanders said. “But I do think it is appropriate to acknowledge that taxes will go up.”

TWITTER

Perhaps it was the product of a debate that lasted three hours, but a question about the power of big tech companies turned into a squabble over the Twitter account of President Trump. Again, Warren was taken to task.

Sen. Kamala Harris, in fifth place, wanted to push Trump off the social media platform -- and pointedly wanted to know why hasn’t Warren joined her?

“I just want to say that I was surprised to hear that you did not agree with me that on this subject of what should be the rules around corporate responsibility for these big tech companies, when I called on Twitter to suspend Donald Trump's account, that you did not agree,” Harris attacked.

“I don't just want to push Donald Trump off Twitter. I want to push him out of the White House. That's our job,” Warren responded.

FOREIGN POLICY

Tuesday showcased perhaps the most serious exchange of ideas on foreign policy by the candidates. Two military veterans, Hawaii Rep. Tulsi Gabbard and Buttigieg, did most of the sparring.

She had flirted with the idea of boycotting the debate and she polls at less than a percentage point, but Gabbard held nothing back when asked about the U.S. military withdrawal from Syria.

“The slaughter of the Kurds being done by Turkey is yet another negative consequence of the regime-change war that we’ve been raging in Syria,” she argued. “Donald Trump has the blood of the Kurds on his hands, but so do many of the politicians in our country from both parties who have supported this ongoing regime-change war in Syria that started in 2011, along with many in the mainstream media.”

Buttigieg, who served a deployment in Afghanistan, did not take kindly to that charge. Gabbard, he said, was “dead wrong.”

The deaths of Kurds as Turkey advances into northern Syria, he insisted, was the result of the U.S. retreat.

American “soldiers in the field are reporting that for the first time, they feel ashamed, ashamed of what their country has done,” Buttigieg said. “When I deployed, I knew one of the things that was keeping me safe was the fact that the flag on my shoulder represented a country known to keep its word, and our allies knew it, and our enemies knew it.”

“You take that away, you are taking away what makes America, America,” he said. Gabbard shot back that he supported deploying the military for “an indefinite period of time to continue this regime-change war.”

GUN CONTROL

The Democrats onstage did agree on reducing the number of so-called assault weapons in circulation, what they roundly decried as weapons of war. Then they fought over how best to accomplish that mission.

At the last debate, former Texas Rep. Beto O’Rourke said, “Hell, yes, we're going to take your AR-15, your AK-47." The candidate in a distant sixth place did not say on Tuesday night how he would do that, other than to insist SWAT teams wouldn't go on confiscation raids.

“We don't go door to door to do anything in this country to enforce the law. I expect Republicans, Democrats, gun-owners, non-gun-owners alike to respect and follow the law,” O’Rourke said Tuesday.

But, the moderator noted, there are a lot of these guns in circulation, the government doesn’t know who owns them and there is nothing in his proposal other than a belief in the inherent goodness of gun owners to follow a prospective ban.

O’Rourke said police would confiscate the guns on a case-by-case basis if they were brandished in public. Buttigieg, who accused O’Rourke of backing mandatory buy-backs to stay relevant, said his opponent was pushing too far too fast at the expense of other possible reforms.

“Look, Congressman, you just made it clear that you don't know how this is actually going to take weapons off the streets,” he said. And worse, in Buttigieg’s estimation, the controversial question of buy-backs made passing universal background checks and banning high-capacity magazines and creating more red-flag laws more difficult: “We cannot wait for purity tests. We have to just get something done.”

Citing mothers and children who are demanding a ban, O’Rourke responded that it was time to “do what’s right” and to “follow their inspiration and lead and not be limited by the polls and the consultants and the focus groups.”

Buttigieg, again more aggressive than in previous showings, shot back that he didn’t “need lessons from you on courage, political or personal.”

FREE MONEY OR A GUARANTEED GOVERNMENT JOB?

Andrew Yang has been a curiosity candidate for much of the race, a tech entrepreneur turned politician with one prominent proposal that has kept him qualified for the debate stage. Namely, universal basic income.

Yang brands it as a “freedom dividend.” His answer to inequality and a changing labor marketplace is a $1,000 monthly check from the federal government. He was given the chance Tuesday night to contrast that with the job guarantee promised by Sanders.

“The fact is, most Americans do not want to work for the federal government. And saying that that is the vision of the economy of the 21st century to me is not a vision that most Americans would embrace,” Yang argued.

This led to exchanges about automation and job loss. Warren insisted the real problem is big corporations. Former Housing and Urban Development Secretary Julian Castro, who stands at 1%, said he is open to the idea of trying UBI, and Gabbard embraced it.

Will the federal government start mailing checks to every American or put them on payroll? No consensus emerged, but what was previously an academic proposal to fix a very real economic problem was given significant billing in prime time — a win for a candidate often written off by party brass and cable news.

WEALTH TAX

New ideas are not always well received but Sanders and Warren have succeeded in remaking a large part of the party in their ideological image. One marquee indicator of this accomplishment: a wealth tax.

The two Northeast liberals back the idea to different degrees but with the same goal. The rich ought to be taxed to pay for new government benefits, they argue, be it free health care, free college, free childcare. But while no one on stage stood up for the property rights of billionaires -- including first-time debater Tom Steyer -- moderates questioned the proposed measure. Again, Warren took the brunt of the attacks.

"I'm all for a wealth tax. I'm all for just about everything that was just mentioned in these answers," Buttigieg said. “Let me tell you, though, how this looks from the industrial Midwest where I live: Washington politicians, congressmen and senators saying all the right things, offering the most elegant policy prescriptions, and nothing changes.”

Klobuchar joined in singling out Warren: “It could work. I am open to it. But I want to give a reality check here to Elizabeth, because no one on this stage wants to protect billionaires," she said. "We just have different approaches. Your idea is not the only idea.”

IMPEACHMENT

Each of the candidates wants to win the presidency. None wants to wait until the election to decide whether Trump should stay or go from the White House. They agreed that the House should impeach the president.

“Rudy Giuliani, the president and his thugs have already proven that they, in fact, are flat lying,” Biden said, referencing Trump’s attempt to dig up dirt on the former vice president with the help of Ukrainian officials. “What we have to do now is focus on Donald Trump. He doesn’t want me to be the candidate. He’s going after me because he knows if I get the nomination, I will beat him like a drum.”

All agreed that impeachment was just and pledged their support for the inquiry. Buttigieg added his own flavor, encouraging the field to look to the future and issues that would persist even if Trump is forced from office.

HUNTER BIDEN

The latest impetus for impeachment -- the call between Trump and his Ukrainian counterpart concerning Biden’s son -- did not get much attention.

The president and his personal attorney have accused Hunter Biden of trading on the name of his father to secure business deals in both Ukraine and China, alleging corruption when the former vice president was still in office.

The senior Biden roundly rejected those claims: “Look, my son did nothing wrong. I did nothing wrong. I carried out the policy of the United States government in rooting out corruption in Ukraine. And that's what we should be focusing on.”

The moderators seemed happy to move on, but Cory Booker later condemned them for doing the bidding of the incumbent.

“I am having deja vu all over again,” he said when answering an unrelated question. “I saw this play in 2016's election. We are literally using Donald Trump's lies, and the second issue we cover is elevating a lie and attacking a statesman. That was so offensive. The only person sitting at home that was enjoying that was Donald Trump seeing we are distracting from his malfeasance and selling out of his office.”