In a crowded field of Democrats vying for the presidency in 2020, one thing stands out. "Medicare-for-all" tops their campaign promises. On Sunday, the latest to announce, former Obama cabinet official Julian Castro, pledged to make Medicare-for-All a reality.

But these candidates would rather walk on hot coals than tell you what "Medicare-for-all" costs: a whopping $32 trillion over 10 years. To raise that, all taxpayers, not just the rich, would have to hand a gut-wrenching share of their paycheck to Uncle Sam, based on Congressional Budget Office revenue tables.

A single guy earning $82,500 a year, and currently paying a 24 percent marginal rate, would be hit with a 60 percent tax rate. A couple reporting $165,000 in income would also see their marginal rate soar from 24 percent to 60 percent. No more dinners out or family trips. Goodbye to their standard of living.

And goodbye to America's standard of care. Liberals want to keep the name Medicare, but change everything else. The result will be stingy care for all. Here's why:

Currently, Medicare pays doctors and hospitals about 87 cents for every dollar's worth of care, according to the American Hospital Association. Why do doctors and hospitals go along with the shortchanging? Because they can shift their unmet cost onto younger, privately insured patients. But "Medicare-for-all" outlaws private insurance. All patients would be underpaying, leaving hospitals with less money. "Many hospitals wouldn't be able to keep their doors open," says Chip Kahn of the Federation of American Hospitals. Those that do will be jamming more beds in a room, and making patients wait longer for a nurse.

That could be you. If you have insurance now, you won't be allowed to keep it. Nationwide, the 156 million people getting coverage through a job would be forced to give it up. Employers and unions would be barred from covering workers or their families. Public unions are already protesting. Everyone would get the same coverage, employed or not. What's the incentive to work?

Instead of facts, Democrats are offering happy talk. Last week, Mayor Bill De Blasio boasted that "from this moment on in New York City, everyone is guaranteed the right to health care." And this promise is not just for emergency room visits; he means a primary care physician. De Blasio put the cost of covering 600,000 uninsured at $100 million a year and said no tax hikes are needed. That miracle math works out to $170 per person. In truth, it won't pay for one doctor's visit, much less tests or medications.

But this urban Robin Hood knows he'll need more. At his State of the City speech, he said, "Brothers and sisters, there's plenty of money in the world; plenty of money in this city. It's just in the wrong hands." Meaning the hands of the people who earned it.

Sanders' approach is only slightly less confiscatory. There's no disputing the $32 trillion cost of "Medicare-for-all," according to the left-leaning Urban Institute and the right-leaning Mercatus Center. Sanders proposed hiking the capital gains tax rate as high as 64.2 percent. That would torpedo economic growth. He also proposed an unprecedented tax on wealth. Even these radical ploys would raise less than half the cost, according to the Tax Policy Center.

Democrats have to decide whether they're the party of capitalism or confiscation. Some Dems are pledging to soak the rich and others are catering to them. Democratic Rep. Nita Lowey of New York is pushing to restore full tax deductibility of state and local taxes, benefitting her well-heeled constituents. In the midterms, Democrats swept the 10 richest congressional districts in the nation. It's becoming the party of the ultra-rich and the very poor. "Medicare-for-all" offers nothing for the vast middle -- the working people.

That's a huge opportunity for Republicans. They need to offer practical fixes for the unaffordable deductibles and suffocating paperwork that make people angry. And they need to remind voters that massive tax hikes to pay for single-payer health care will destroy economic growth, robbing all of us, rich, poor and middle class alike.

Betsy McCaughey is a former lieutenant governor of New York state. Contact her at betsy@betsymccaughey.com.