The vast majority of Americans, 70 percent, now support Medicare-for-all, otherwise known as single-payer health care, according to a new Reuters survey. That includes 85 percent of Democrats and 52 percent of Republicans. Only 20 percent of Americans say they outright oppose the idea. "Medicare is a very popular program, so the idea of expanding it to everyone is popular as well," Larry Levitt, senior vice president for health reform at the Kaiser Family Foundation, tells CNBC Make It. "The advantage of Medicare-for-all, which is much closer to how the rest of the world provides health care to their residents, is that you can achieve universal coverage at a lower cost."

The problem with health care in the US

For at least a decade, most Americans have been dissatisfied with the country's largely for-profit health-care system, according to Gallup. In a poll last year, 71 percent of respondents said the system is "in a state of crisis" or "has major problems." Health care in the U.S. is criticized primarily for its inefficiency, inaccessibility and ever-rising costs. The average annual deductible for employer-sponsored health care plans, which make up most of the plans in the U.S., was $1,505 in 2017, compared to $303 in 2006, according to the KFF. Last year workers paid on average $5,714 toward their cost of coverage by way of monthly premiums, a 3 percent increase from the year before.

What Medicare-for-all would change

Reuters defines Medicare-for-all as "a publicly financed, privately delivered system with all Americans enrolled and all medically necessary services covered." In theory, it would solve some of the main issues of America's current system. Sen. Bernie Sanders proposed his Medicare-for-all bill in September of 2017. It aims to gradually reduce the uninsured rate, which currently sits around 12 percent, until it reaches 0 percent, by enrolling everyone in a nationwide public insurance plan. Under his proposal there'd be no more deductibles or co-payments. Although there's no opting out, people would have the option to buy supplemental care through private insurers. The bill has little chance of passing with a Republican majority in Congress, as Sanders has conceded. Right now it's just setting up Democrats for potential legislation in the future and bringing attention to drawbacks of the current American system, he says, such as exorbitant spending and high drug prices.

A single-payer system simplifies who is responsible for covering costs. That gets rid of some of the issues that stem from the complexity of the current American system, like balance billing. In a recent incident reported by NPR that's since gone viral on social media, Drew Calver, a 44-year-old teacher and triathlete in Austin, Texas, had a heart attack. He was rushed to an out-of-network hospital and had stents implanted. A network is a list of hospitals, doctors and other medical providers who are covered by a person's health plan. Out-of-network providers are either not covered at all, or are covered at a much lower rate, leaving the patient responsible for much or all of the resultant bill. Almost 18 percent of hospital admissions end up with some out-of-network claim, often because someone goes to an in-network hospital but ends up getting care from an out-of-network physician. Among those who can't afford the ensuing costs, most say they didn't realize they were receiving care outside their insurance network. Calver went home after four days. Though he asked from his hospital bed and was assured that his insurance would be accepted, his portion of the bill came to almost $110,000. That's "nearly twice his annual pay," NPR notes. "Under a pure Medicare-for-all plan, those issues would go away," Levitt says.

What it might cost