Public support for single-payer health care is soaring. Seven in 10 Americans want to adopt a “Medicare for All” system, according to a recent Reuters/Ipsos poll.

This shift in public opinion has been good news for Democrats. The party took back the House in part by promising to make voters’ supposed dreams of government-run health care come true. Two-thirds of incoming House Democrats campaigned on some form of “Medicare for All.”

Let’s hope those promises were empty. If single-payer health care ever comes to pass, patients will regret their embrace of it. As President Trump and his team are fond of pointing out, Medicare for All would rapidly devolve into Medicare for None.

Democratic lawmakers have proposed several bills that would hand the government control over our healthcare system to varying degrees.

Sen. Bernie Sanders’ 2017 single-payer bill, whose 16 co-sponsors include four likely Democratic candidates for president, would outlaw private insurance and place virtually all Americans in a standardized government-run health plan. It would even eliminate the Medicare Advantage plans, which are run by private insurers, that one in three Medicare beneficiaries enjoy. The government would pay all medical bills and regulate which procedures and treatments are covered.

The House equivalent of Sanders’ bill had more than 120 co-sponsors in the last Congress. A House Medicare for All caucus co-founded by Rep. Pramila Jayapal, D-Washington, has 77 members. And Sanders and Jayapal will introduce updated versions of Medicare for All legislation in the Senate and the House.

Some Democrats are pushing for a slower march toward single-payer. The Medicare-X Choice Act would make Medicare plans available to all consumers through Obamacare’s insurance exchanges. The Choose Medicare Act would allow individuals and employers to buy into Medicare.  And the State Public Option Act would enable people to buy into state Medicaid plans.

Some state legislators are not waiting for Congress to act. For the last four years, the New York Assembly has passed the New York Health Act, which would install single-payer in the Empire State. Now that Democrats have taken control of the state Senate for the first time in eight years, that bill could advance.

In 2017, the California state Senate passed a measure that would establish single-payer within the Golden State. The assembly shelved the proposal over concerns about its cost. But the state’s newly elected governor, Democrat Gavin Newsom, is on record in favor of the approach. So don’t expect the issue to go away anytime soon.

Promising state-funded health care to everyone is easy. Paying for it is a lot harder.

According to Charles Blahous, a scholar at the Mercatus Center, Sanders’ bill would increase federal spending by at least $32 trillion in the first decade — even as it cut payments to providers to Medicare rates, which are 40 percent below those paid by private insurance. Doubling individual and corporate income tax receipts would not be enough to meet that tab.

Despite those substantial outlays, doctors say Medicare for All won’t cover their cost of practicing medicine. In an interview with MedPageToday, Dr. Barbara McAneny, the president of the American Medical Association, said that if all her patients paid Medicare rates, “My doors would be closed. I would no longer be able to make payroll.”

California’s plan would cost $400 billion a year, according to a 2017 analysis. The state would have to collect an extra $200 billion in taxes. That hasn’t sat well with ordinary Californians. According to one survey, support for single-payer drops from 53 percent to 41 percent when voters find out that their taxes would increase.

Despite its high cost, single-payer delivers poor care. When care is “free,” people have no reason to limit their use of medical services. The government has to ration care to keep costs from spiraling out of control.

Look at Canada. The median wait time to obtain treatment from a specialist after receiving a referral from a general practitioner has more than doubled since 1993, to just under than 20 weeks.

The United Kingdom’s National Health Service is also in crisis. Wait times have surged, and there aren’t enough beds for all patients. This summer, the number of people on waiting lists hit 4.3 million — a 10-year high. Among the proposed responses are group appointments, where doctors see 15 patients at once.

Crippling costs and waits are characteristic of single-payer health care. The American public must realize that the road to Medicare for All is paved with steep tax hikes, doctor shortages, long waits and government rationing.