Where Bullock defended his opposition to "Medicare for All," de Blasio touted the sweeping health care plan.

Where de Blasio talked about there not being much of a divide between rural and urban voters, Bullock pushed his ability to relate to people in rural states -- like Montana -- who voted for President Donald Trump.

And where Bullock talked about his concerns about mandatory gun buybacks and his past opposition to universal background checks, de Blasio pledged -- as president -- to make gun legislation a central issue.

Despite their differences, the question for both men is whether they were able to break out of their low-tier status in the Democratic race, where both Bullock and de Blasio find themselves polling under 1% in most surveys.

Those results have put them as risk of missing both the September and October Democratic National Committee debates, an outcome that could imperil both campaigns.

Here are the key takeaways from CNN's town halls with Bullock and de Blasio:

Where Bullock worries about starting over on health care...

Bullock defended his opposition to the single payer Medicare for All proposal, setting him apart from more progressive Democrats running for president like Vermont Sen. Bernie Sanders and Massachusetts Sen. Elizabeth Warren.

Medicare for All would shift control over the health care system to the federal government and essentially eliminate the private insurance industry.

Bullock said the "greatest stride" the country has made on health care is the Affordable Care Act, the sweeping health care law also known as Obamacare that was signed by President Barack Obama.

"I don't think the best way is to start all over. I don't want to take away employer-sponsored health care," Bullock said. "I look at this as an add-on, not a complete teardown."

He added: "The way we get to full access and affordability isn't to start over. It's to build on what we have."

de Blasio champions wholesale change

New York City Mayor Bill de Blasio said he wants to "make sure people get health care from the beginning" so patients don't turn to emergency room visits as a means of health care.

His proposal: Medicare for All.

"There should not be such a thing as an American who doesn't have insurance or doesn't have health care. That should be a thing of the past," de Blasio said.

Where Bullock worried about costs, de Blasio argued that the plan would be cost effective because Americans would pay more in taxes but less in health care bills.

And de Blasio took on some of his Democratic opponents over the issue.

"This idea that, even in a lot of the Democratic Party debates, we're sort of arguing over, you know, well, we could get a little better here or a little better there. That's not what we should be talking about as Americans," he said. "We should talk about how every American gets quality health care. Physical health care, mental health care. Quality health care when they need it. That should be the goal of this country."

de Blasio dismisses the divide between urban and rural Americans

The New York mayor said on Sunday that the divide between urban and rural America, a rift that is seen as widening in recent years, is not as stark as most people believe.

De Blasio argued that all Americans want generally the same from life, telling the audience at a CNN town hall that people in "rural counties" and "folks who live in smaller town" are asking him about "literally nearly identical (issues) to what I heard from my constituents here in the five boroughs."

"I really don't see the divide as much as I think it's projected to all of us," de Blasio said. "I think there's a lot more commonality of feeling and interest."

The divide between urban and rural voters was most stark during the 2016 election, where Trump overwhelmingly won rural voters in 2016, while urban voters backed Democrat Hillary Clinton.

But de Blasio said that divide is not as clear as it was on Election Day in 2016.

De Blasio's answer stands in stark contrast to Bullock, who has run for president by touting himself as the best candidate to win back red states.

Bullock delivers 'absolute no' to Senate run

Democrats are all but begging Bullock to run for Senate.

They can stop, the governor said Sunday.

"So that's an absolute no," CNN's Alisyn Camerota asked.

"That's an absolute no," Bullock responded.

As eager as Democrats are to oust Trump from office, many are worried about the US Senate, where the Democratic Party is currently in the minority. That concern has extended to the presidential race, where a number of Democrats from states with important Senate races are vying for the top job.

Bullock said his issue with running for Senate are three-fold: professional, political and personal.

"Part of it is professional, meaning the whole time I've served as an executive, I've been able to bring people together to get things done. I think that's where my talents are best suited," he said.

Politically, he said, he thinks it is important for the Democratic Party to better understand why it is losing states like Montana.

And lastly, Bullock said, he wants to spend more time with his kids.

"I know President Obama had dinner with his kids a lot more than I would as a senator from Montana," Bullock concluded.

Bullock, de Blasio want action on guns, but see different paths

Bullock blamed the National Rifle Association, an organization that he said was just a "gun safety and hunting organization" when he was young, for stalling any movement on gun control legislation.

Bullock only came out in favor of universal background checks in 2018, far later than most Democrats, and he comes from a state with a proud culture of gun ownership and hunting.

But Bullock explained on Sunday that he softened his position on guns because of the 2018 shooting at Stoneman Douglass High School in Parkland, Florida, that left 17 people dead and listening to his children after the shooting.

"I'll give you a reason why we can't look at it as just a public health issue. In fact, I'll give you 30 million reasons. That's how much the NRA spent to make sure that Donald Trump was elected," Bullock said. "When I was growing up, the NRA used to be a gun safety and hunting organization. Now it's a dark money field, political organization, that does nothing than drive us apart."

But Bullock still opposes mandatory buy backs for assault weapons, a position that de Blasio supports.

"How about we, the American people, say enough with the NRA's dominance of the Congress," de Blasio said. "Because a clear majority of Americans want more extensive background checks. They want to close the gun show loophole. They want waiting periods. They want a ban on assault weapons. These things can actually happen."

Garner tragedy follows de Blasio

The death of Eric Garner at the hands of officer Daniel Pantaleo in 2014 continues to hang over de Blasio.

Five years after Garner's death, Pantaleo was fired from the New York Police Department a week ago. De Blasio had blamed the Department of Justice over the handling of the case, but that explanation did not satisfy many in New York, some of whom vocally and directly protested the mayor.

De Blasio looked to move past the issue on Sunday, telling CNN that the incident taught him that the city "had to do pretty much everything differently."

"There needs to be federal leadership that says de-escalation training, implicit bias training, body cameras, every police officer in America should have those. Every single one," he said. "That's how we end the tragedies."

But the impact that the death continues to have on de Blasio was clear shortly after his answer when a woman in the audience faulted the mayor for Pantaleo's dismissal taking five years.

"What about Lieutenant Bannon? What about officer Ramos? What about other officers," the woman shouted.

De Blasio did not answer the woman's question.