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It seems like just yesterday that Democrats were telling us that under Obamacare, "If you like your doctor, you can keep your doctor. If you like your health care plan, you can keep your health care plan."

That was a nice sales pitch to voters -- even though it turned out to be a lie. Millions of Americans lost affordable insurance plans that were abolished under the Affordable Care Act. Still, people liked the idea that poor people would get health coverage and everyone else could retain the medical care they had.

No more. When Bernie Sanders, and half the Democrats running for re-election, promising "Medicare-for-all," they mean exactly what they say. This is a health plan for all; everybody is tossed in the swimming pool.

Think about that. Health and Human Services now tells us that some 157 million Americans with employer health care plans -- more than the entire population west of the Mississippi River -- would be forced into Medicare. If you don't like that idea, tough. Bernie knows best.

Democrats are denying this is true, but in the Nancy Pelosi tradition, they haven't read their own bill. There are several variations of "Medicare-for-All," but one prominent version makes private plans that would compete with Medicare illegal.

Under Title VIII, Section 801 of the Medicare for All Act of 2017, the bill specifies that "no employee benefit plan may provide benefits that duplicate payment for any items or services for which payment may be made under Medicare." In other words, employers are prohibited from covering workers, retirees and their families.

Medicare already imposes all sorts of restrictions on private health plans for seniors that would dare compete with or undercut Uncle Sam. This is what "single-payer" means.

Republicans have been complaining that "Medicare-for-All" will jeopardize Medicare for seniors. Yes, but that isn't the bill's biggest political poison pill. Republicans should be shouting from the mountaintops: Nearly half of Americans will lose their health care under Sanders' wild adventure. If voters knew this fact, it would surely cause a pitchforked revolt of the middle class. Polls show that more than 70 percent of Americans with private health plans like what they have.

In nearly every country with single-payer health systems that Sanders boasts about for being so "cost-efficient," private insurance becomes either illegal or financially unavailable except for the superrich. The entire premise of government-run care, as we saw under Obamacare, is that single-payer cannot work unless everyone -- healthy and sick -- is vacuumed into the same giant insurance pool so as to avoid "adverse selection" and a death spiral in costs.

Under the Canadian system, "Private insurance for medically necessary hospital and physician services is illegal in only 6 of the 10 provinces," a recent news agency reports. "A significant private sector has not developed in any of the 4 provinces that do permit private insurance coverage," the report continues. As Henry Ford used to say about the Model T when he was asked if you could get it in any color you wanted, "Yes, as long as it's black."

Americans don't have to imagine what a government-run system would look like. We have one that already covers millions of Americans. It is called the Veterans Health Administration. Our veterans die waiting in lines and hospitals often provide shoddy levels of care -- to the very people who have, through their service and sacrifices, earned the best care in the world.

In 2018, Democrats have made "Medicare-for-All" their nationwide rallying cry. Republicans need to tell Americans the real story: Beware, ladies and gentlemen. The Bernie Democrats are coming to take away your health coverage and that of 157 million other Americans -- whether you like your current plan or not.

Stephen Moore is a senior fellow at The Heritage Foundation and an economic consultant with FreedomWorks. He is the co-author of "Fueling Freedom: Exposing the Mad War on Energy."