Democratic Presidential Debate: 5 Moments That Mattered in Flint, Michigan

— -- Hillary Clinton and Bernie Sanders went head-to-head on a debate stage here Sunday night against the backdrop of the water crisis afflicting the city.

But the debate, hosted by CNN, took place at a critical moment in the Democratic primary season when both candidates are in the midst of a state-by-state fight for delegates. And there was no shortage of tense moments between the two contenders.

However, both candidates positioned themselves -- and their debate -- as stark contrast to the Republican field.

“Compare the substance of this debate with what you saw on the Republican stage last week,” Clinton said. Sanders backed her up: “We are, if elected president, going to invest a lot of money into mental health, and if you watch these Republican debates, you know why.”

Here are 5 moments that mattered at Sunday night’s debate:

1. Clinton Calls For Michigan Governor’s Resignation

Clinton joined Sanders for the first time tonight in calling for Michigan’s Republican Gov. Rick Snyder to resign because of the water crisis in Flint.

“I agree,” Clinton said in her opening remarks, echoing Sanders. “The governor should resign or be recalled."

Sanders first called for the governor’s resignation in January.

Both candidates were asked Sunday night whether they would fire the head of the Environmental Protection Agency or whether people should be jailed because of the government’s failure to prevent the high levels of lead found in residents’ tap water.

“There has to be absolute accountability,” Clinton said, “And I will support whatever the outcome of these investigations.”

Sanders added: “President Sanders would fire anybody who knew what was happening and did not act appropriately.”

2. ‘Excuse Me, I'm Talking’

Who bailed out whom?

Sanders and Clinton raised their voices and tried to speak over each other in the issue of bailouts. The moment got nasty for the two Democrats who normally stay rather cordial.

Clinton first tried to say Sanders voted against the auto-industry bailout. Sanders in turn, hit Clinton over her support of the Wall Street bailout, which funded the auto industry bailout.

The former Secretary of State tried to interject, but Sanders wasn’t having it: “Excuse me, I’m talking,” Sanders said.

(The Senator did support the idea of the auto bailout and voted for it in 2008, but voted against the second part of a Wall Street bailout package which the Obama administration used to pay for the auto industry bail out in 2009.)

3. Sanders Defends Being A ‘One-Issue Candidate’

On the campaign trail, Clinton has repeatedly cast Sanders as a Marco Rubio-esque robot who can only engage on one-issue (“I am not a single issue candidate, and this is not a single-issue country,” she often says). And tonight, Sanders embraced it.

“Secretary Clinton said I’m a one-issue candidate person. I guess so,” he said. “My issue is trying to rebuilding a disappearing middle class. That’s my one issue.”

The remark came as the two candidates sparred over the auto bailout – which Clinton supported and Sanders, for the most part, did not.

“All I can say is that given the terrible pressures that the auto industry was under and that the middle class of this state and Ohio and Indiana and Illinois and Wisconsin and Missouri and other places in the Midwest were facing,” Clinton said, “I think it was the right decision to heed what president-elect Obama asked us to do.”

“I will be damned if it was the working people of this country who had to bail out the crooks on Wall Street,” Sanders said.

4. A Personal Question On Gun Control

The father of a teenager critically injured in last month’s shooting spree in Kalamazoo, Michigan questioned the candidates over gun control issues.

“The man who shot everyone including my daughter in Kalamazoo had no mental health issues recorded and a clear background. What do you plan to do to address this serious epidemic?” Gene Kopf asked, adding: “I don’t want to hear anything about tougher laws for mental health or criminal backgrounds because that doesn’t work." (Kopf noted that his daughter, who was on life support after the shooting, "is now laughing and giggling and has a long road to physical recovery").

"I'm very grateful that she is laughing and she is on the road to recovery," Clinton said, reiterating her call for comprehensive background checks and closing the online and so-called Charleston loopholes that make it easier for people to buy guns.

Sanders also pledged his support for closing the Charleston loophole, named for the shooting at a church in Charleston, South Carolina, where the alleged gunman was able to buy guns despite having a felony conviction on his record because the background check took more than 72 hours.

He said the country should "do everything we possibly can to minimize the possibility of these mass killings."

5. Who Loves The 90s?

Several of Sanders' critiques of Clinton centered on initiatives pursued by her husband in the 1990s. The former First Lady took note. After the senator railed against what he sees as the negative impacts of free trade agreements such as NAFTA, Clinton said she preferred to talk “about the future” instead of arguing about policies from two decades ago.

Later, the two sparred about poverty versus income and employment levels in years past. Sanders accused Clinton of backing a welfare reform bill, which progressives say hurt the nation’s poorest and most vulnerable.

Clinton countered: “If we are going to talk about the 90s, let's talk about 23 million new jobs and incomes went up for everybody,” she said.

But in the end, Sanders seemed to have the last word.

“Secretary Clinton is right. The 1990s created jobs and I supported many of your husband's initiatives,” he said. “You know we deregulated Wall Street that allowed it to end up destroying our economy. We passed NAFTA and other disastrous trade agreements that had a horrendous impact on African-Americans in particular in Detroit and all across this country. A lot of good things happened, but a lot of bad things happened.”