Here's the thing about Medicare For All: It's front and center in this year's presidential election (OK, next year's election. But who's counting?), a prime topic at the four Democratic debates held thus far.

It's also a bright line dividing progressive, left-wing Democratic candidates like New England senators Elizabeth Warren and Bernie Sanders from moderate centrists like former Vice President Joe Biden and Minnesota's Sen. Amy Klobuchar, and it has become a proxy for which constituency Democrats believe will matter the most on Election Day: Progressives and marginalized voters, or the moderate, working class whites who left the party in 2016.

And that bright line has all but stymied any kind of substantive conversation about Medicare For All. You're for it, or you're against it.

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But real debate is important. Even if you believe, as I do, that health care is a basic human right — even if you are completely on board with both the moral urgency of and the business case for ensuring that all Americans have access to health care — it's OK to have questions about how such a sweeping program could be implemented. And it's not selfish or immoral to wonder what it would mean for you or your family.

To sell Medicare For All to voters, especially voters who have private insurance, these are the questions Democrats who support it need to address squarely:

The obvious questions

Left- and right-leaning policy shops put the Medicare-For-All price tag around $32 trillion over 10 years, an astounding number that some analysts say would nevertheless represent a small decrease in overall healthcare spending.

But what most folks — even the ones who believe in universal health care— want to know: What will it cost me?

Sanders and Warren, both of whom would raise taxes on the wealthiest Americans to pay for their programs, say any tax increase on middle class families would be offset by the elimination of insurance premiums and most other healthcare costs. But those numbers are incredibly hard to pin down. We're taxed at different rates, and Americans with health insurance pay wildly varying amounts for premiums, co-pays, office visits, specialist visits and prescriptions, which we draw on at wildly varying rates.

It doesn't help that there multiple iterations of this kind of plan. But at the root, candidates should be able to give voters some sense of how we'll pay for it, and how it will work.

Why will it be better?

Almost any kind of health coverage would be an improvement for those who are currently uninsured. But even for those us with employer-based healthcare plans — and really, these are the voters who will need to buy into Medicare For All — dealing with health insurance is often a nightmare.

For most of us, benefits have gotten worse, year after year. We've seen our employers changes plans or insurers with little or no notice, rarely to our benefit. Getting authorization for routine care or prescriptions can consume hours. Those of us lucky enough to enjoy union representation have watched our negotiators fight a losing battle to keep what we've got.

You'd think we'd be ready to jump ship. But ... we're used to it, and when it comes to health insurance, "change" has nearly always meant "worse."

Candidates who support Medicare For All need to articulate clearly why a single-payer system will result in better outcomes, with regard to cost, national healthcare spending, the stability of the system, and the ease of interacting with it.

Healthcare is like plumbing. No one wants to have to think about it. We just want it to work.

What countries provide models for implementing a single-payer system?

We're late to the single-payer game. The United Kingdom's National Health Service developed after World War II. Canada's single-payer system dates to the 1960s.

In the intervening decades, the healthcare landscape has become increasingly complex. The rates hospitals and doctor's bill for the same procedures vary widely, for reasons ranging from personnel to facilities costs. What would it be like to impose fixed costs on such a system? And has anyone else done it?

"The only single payer system that emerged from an already developed system of which I'm aware is South Korea's," John McDonough of Harvard University's T. H. Chan School of Public Health wrote in an email. "Other than that, I can't think of any.

"(Questions) about the feasibility of moving to uniform and unitary payment from within our current mix are valid. Any change would produce many winners and many losers, all depending on levels of reimbursement and other vital details, none of which have been fleshed out in any meaningful way in any of the current proposals."

Would would abolishing private insurance mean?

Sanders' Medicare For All proposal would bar private insurance companies from offering any product that duplicated government insurance. Insurance is a giant, profit-making industry. If the U.S. Congress makes it illegal, you'd be nuts not to expect lawsuits.

So I called someone who does: University of Michigan law professor Sam Bagenstos, who patiently answered all of my questions, even the hypothetical one about what would happen if Congress banned cupcakes.

Lawsuits, he said, would certainly happen.

Congress is on solid footing when it comes to regulating commerce, Bagenstos said, and regulating commerce includes the power to prohibit commerce. The federal government has banned the sale of interstate lottery tickets, prohibits the sale of marijuana and other drugs, and outlaws chemicals scientists agree are harmful.

But whether a prohibition like Sanders' would stick, Bagenstos says, depends on the makeup of the U.S. Supreme Court: "There is a line of thinking among conservative judges who don’t have a majority on the U.S. Supreme Court right now, but could at some point in the future, that the due process clause protects right to enter into contracts."

What would happen to people who work for private insurers?

Not CEOs with infuriatingly high salaries. I mean the the poor schlub at the employee benefits call center, the one whose job is to explain why the company whiffed on your last big bill.

The Insurance Information Institute says that of the roughly 2.7 million Americans who worked in the insurance industry in 2017, about 870,600 were employed in the health and life insurance sectors. Some would likely find jobs in the new single-payer system. But one of the ways a single-payer system would save money is by streamlining the health insurance bureaucracy. Even in the big picture, 800,000 newly unemployed workers is more than a blip (6 million Americans are currently unemployed, per the U.S. Bureau of Labor and Statistics). You could argue that it's a short-term sacrifice for a system that will greatly improve the lives of most Americans. And you might be right, but I wouldn't like to make that case to health insurance industry employee #371,363.

"Presumably, a drastically reduced health insurance industry would remain to provide supplemental coverage for benefits and, perhaps, cost sharing not covered under a new federal play, much like 90% of Medicare enrollees today have some kind of supplemental coverage," Harvard's McDonough wrote. "It would be a much smaller industry, with far less influence and power, which is why they would fight to the death to prevent this from happening."

Nancy Kaffer is a Free Press columnist. Contact: nkaffer@freepress.com.