Related: Medicare for All: Where the 2020 presidential candidates stand

Health care offered each candidates a potent opportunity. Former Maryland Rep. John Delaney argued that Medicare for All would “get Trump reelected.” Gov. Steve Bullock of Montana spoke to the plight of the teacher “working a second job to afford her insulin.” And former Colorado Gov. John Hickenlooper, who opposes Medicare for All, spoke of how he expanded health care — a claim we rated mostly true earlier this year when he spoke about steps he took toward achieving universal coverage.

But even as the candidates put their markers down on the ideological spectrum, not all of their claims fully stood up to scrutiny.

We fact-checked some of those remarks.

SANDERS: “Right now, we have a dysfunctional health care system. Eighty-seven million uninsured or under-insured, 500,000 Americans every year going bankrupt because of medical bills, 30,000 people dying while the health care industry makes tens of billions of dollars in profit.”

That's a lot of numbers for a Tuesday night, and as confidently as Sanders stated them, they rely on complicated data and, arguably, fuzzy math.

In claiming there are 87 million Americans who are uninsured or underinsured, he is citing 2018 data released by the Commonwealth Fund. Compared to the 27.4 million uninsured in 2017, according to the Kaiser Family Foundation, this includes those with insurance who nonetheless experienced high medical costs compared to their household income.

It is not clear how Sanders calculated the number of medical bankruptcies every year. He may be referring to a study released in February that found an estimated 530,000 families file for bankruptcy each year due to medical bills. However, typically there are many factors that play into filing for bankruptcy, making it difficult to pin on medical costs alone.

And though he did not complete the thought, this is not the first time that Sanders has claimed that 30,000 people die every year because of the high cost of health care. When he tweeted that claim last month, we rated it half true because it appears to rely on weak math.

Former Maryland congressman John Delaney also reiterated a point he used in the first round of Democratic primary debates.

DELANEY: “It's been well documented that if all the bills were paid at Medicare rate, which is specifically — I think it's in section 1,200 of their bill — then many hospitals in this country would close. I've been going around rural America and I ask rural hospital administrators one question: 'If all your bills were paid at the Medicare rate last year, what would happen?' And they all look at me and say, 'We would close.'”

Delaney made this argument to attack Sanders' Medicare for All plan, which he referred to as “bad” policy in his opening statement. He made this claim about rural hospitals during last month's debates, too. We rated it False.

It is undeniable that Medicare pays hospitals a fraction of what private, employer-based insurance pays them. A RAND Health study released earlier this year found private insurers in 2017 paid hospitals 241 percent of the prices Medicare paid, on average.

But the experts we spoke with after the last debate said the effects on hospitals would be more nuanced: While some may take a hit under a Medicare for All system, other hospitals may do better. And it is unclear how much hospitals would be paid under Sanders' plan; that section — it's actually Section 611 — basically says the federal government would decide later how to pay providers.

And O'Rourke took on a public health concern.

O'ROURKE: “The Centers for Disease Control (is) prevented from actually studying (gun violence) in the first place.”

This is an outdated Democratic talking point. The reality is more complicated.

For two decades, spending bills included something called the Dickey Amendment that said, “none of the funds made available for injury prevention and control at the Centers for Disease Control and Prevention may be used to advocate or promote gun control.”

That language remains, but in 2018, lawmakers added, in a separate report, the words “the Secretary of Health and Human Services has stated the CDC has the authority to conduct research on the causes of gun violence.”

Even the original Dickey rule did not totally forbid research.

For a short while at least, the CDC continued to fund studies into the links between firearms and injuries, proof to some people that the Dickey amendment and research could co-exist.

But after 1999, gun research plummeted. David Hemenway, director of Harvard's Injury Control Research Center, told PolitiFact last year that the politics, not the law, drove the CDC's agenda.

“The CDC always had some flexibility, but it wasn't going to fund firearms research since it knew it would, as had happened previously, get hauled before Congress and threatened with reduced funding if any research it sponsored suggested that having more firearms was not good for public health,” Hemenway said.

— PolitiFact's Jon Greenberg contributed to this story.

Kaiser Health News is a nonprofit news service covering health issues. It is an editorially independent program of the Kaiser Family Foundation, which is not affiliated with Kaiser Permanente.

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