The Democratic primary field returned to the debate stage on Sunday night for the last matchup before the first round of voting next month, amid tightening poll numbers and an increasingly raucous race.
With Vermont Sen. Bernie Sanders gaining on longtime front-runner Hillary Clinton in Iowa and New Hampshire, the debate quickly departed from the relatively civil exchanges that defined the last three face-offs. Former Maryland Governor Martin O'Malley, who lags badly in polls, is also participating.
As the race has tightened, Clinton has been on the attack. The former secretary of state and U.S. senator from New York has hammered Sanders for past votes to support immunity from lawsuits for gun manufacturers and criticized his call for a national single-payer healthcare system. She had demanded details on how he would pay for it.
Sanders fired back with an ad criticizing Democrats who take money from Wall Street, an obvious dig at Clinton, and touted his plan to break up the big banks. An angry Clinton campaign quickly accused Sanders of breaking his pledge not to air negative ads against her.
On Sunday night, Clinton rapped Sanders for voting repeatedly with the National Rifle Association, and then welcomed his weekend reversal of position to support legislation that would deny gun manufacturers legal immunity. She rattled off a list of provisions that she said Sanders had supported in line with the NRA.
Sanders, in turn, said Clinton's assertion that he kowtowed to the gun lobby was "very disingenuous" and pointed to his lifetime rating of a D- from the NRA.
On health care, Sanders released his plan for a government-run single-payer plan just hours before the debate, and used his opening statement to call for health care "for every man, woman and child as a right." Clinton, by contrast, urged less sweeping action to build on President Barack Obama's health care plan by reducing out-of-pocket costs and control spending on prescription drugs.
Clinton suggested Sanders' approach was dangerous — and pie-in-the-sky unrealistic.
"With all due respect, to start over again with a whole new debate is something that would set us back," Clinton said.
Sanders dismissed the idea that he'd endanger hard-won victories, insisting: "No one is tearing this up; we're going to go forward."
Clinton suggested Sanders' health care plan would impose a heavier tax burden on the middle class, saying "I want to raise incomes, not taxes."
Sanders insisted taxpayers would come out ahead with lower costs overall. "It's a pretty good deal," he said.
The two tangled over financial policy, too, with Sanders suggesting Clinton won't be tough enough on Wall Street given the big contributions and speaking fees she's accepted.
"I don’t take money from big banks. I don’t get personal speaking fees from Goldman Sachs," Sanders said, adding, "I have huge doubts when people receive money from Wall Street."
Clinton, in turn, faulted Sanders' past votes to deregulate financial markets and ease up on federal oversight.
Then, she took a step back to put those differences in a different perspective.
"We're at least having a vigorous debate about reining in Wall Street," she declared. "The Republicans want to give them more power."
Clinton worked aggressively to associate herself with Obama, claiming credit for her role in the run-up to the Iran nuclear deal as well as praising the health care law.
Overall, the tone of the debate was considerably more heated than the past three face-offs in the Democratic primary. But it also included moments of levity.
At different points, both Clinton and Sanders prefaced their criticism of one another with the phrase "in all due respect."
Sanders took note that he was copying Clinton on that verbiage, drawing a chuckle from his rival.
Then he finished his thought on health care, telling Clinton "in all due respect, you're missing the main point."
Clinton, playing to her liberal audience, cast Sanders' criticisms of Obama for being too weak in taking on Wall Street as unfair, and declared, "I'm going to defend President Obama for taking on Wall Street" and getting results.
"The Republicans just voted last week to repeal the Affordable care Act, and thank goodness, President Obama vetoed it and saved Obamacare for the American people," Clinton said.
Turning to national security, both Sanders and Clinton voiced strong support for Obama's diplomatic overtures to Iran and opposition to sending U.S. ground troops into Syria. Clinton defended her outreach to Russia early in her term as secretary of state, but hesitated when asked to describe her relationship with Vladimir Putin, whose return to the Russian presidency heralded the worsening of U.S.-Russian relations.
"My relationship with him — it's interesting," Clinton said to laughs in the debate hall. "It's one, I think, of respect." But she added it was critical to constantly stand up to Putin, describing him as a bully who "will take as much as he possibly can."
Clinton also shed some light on what role her husband, former President Bill Clinton, would play in her administration. Kitchen table adviser, perhaps?
"It'll start at the kitchen table — we'll see where it goes from there," she said with a laugh.
Then, pointing to the successes of her husband's administration, she added: "You bet I'm going to ask for his ideas. I'm going to ask for his advice."
Sanders was asked about his previous criticism of Bill Clinton's past sexual behavior. He called the former president's behavior "deplorable" but said he wants to focus on issues "not Bill Clinton's personal life." Clinton maintained a tight smile throughout that exchange, and nodded as Sanders said the focus should be on issues.
The debate over gun control — an ongoing area of conflict between Clinton and Sanders — took on special import given the setting: The debate took plan just blocks from the Emanuel African Methodist Episcopal Church where nine parishioners were killed during Bible study last summer. Gun control has emerged as a central theme in the race, with Clinton citing the issue as one of the major differences between the candidates.
O'Malley tried persistently to insert himself into the conversation. He focused on his record as Maryland's governor and accused both Clinton and Sanders of being inconsistent on gun control
The debate perhaps offered O’Malley his last chance to improve his standing in the race. He's been stuck in single digits since announcing his campaign last spring.
O'Malley said investing in cities will be a top priority in his first days in office.
The former Maryland governor said that he would focus on efforts to boost wages, promote clean energy and enhance cities.
The former mayor of Baltimore said, "We have not had a new agenda for America's cities since Jimmy Carter."
O'Malley defended his record in Baltimore and Maryland on criminal justice.
Asked about his crime policies in light of the death of Freddie Gray in Baltimore police custody, O'Malley said Sunday night that "we weren't able to make our city immune from setbacks" but, "we were able to save a lot of lives."