Several lawmakers want to pull more people into Medicare. This would hurt anyone with private insurance, and it would inevitably lead to single-payer, government funded healthcare, which would deprive people of any choice over their healthcare.

Sen. Debbie Stabenow, D-Mich., recently introduced S.470, a bill that would let any citizen or permanent resident between the ages of 50 and 64 buy into Medicare. It received broad support from her Democratic colleagues. Numerous 2020 presidential hopefuls, including Sens. Cory Booker, D-N.J., Kamala Harris, D-Calif., and Kirsten Gillibrand, D-N.Y., have co-sponsored the bill.

Lawmakers in the House of Representatives want to go even further. In December, Reps. Rosa DeLauro, D-Conn., and Jan Schakowsky, D-Ill., introduced a plan called Medicare for America. It would allow anyone in America, regardless of age, to buy into an expanded Medicare system that covers prescription drugs along with dental, vision, and hearing benefits. Those currently covered by Medicare, Medicaid, and CHIP would be shunted onto the new plan, as would anyone who buys policies on the individual market.

These proposals would cause prices for private plans to spike.

Medicare underpays for the services its beneficiaries receive. In 2017, hospitals only received 87 cents per dollar spent treating Medicare patients. That means Medicare underpaid hospitals by $53.9 billion.

As more patients shift to Medicare, providers will have to charge private insurers more to make up the difference. That will result in higher premiums for the privately insured.

In other words, Uncle Sam would charge people twice for Medicare, once through the IRS and again at the doctor's office.

Gradually, people on private plans would get sick of high prices and start moving to Medicare. As people abandoned private plans, insurers would start going out of business. Before long, it would be easy to turn Medicare into an obligatory, single-payer program. That would leave patients with no insurance options.

Patients wouldn't like that. More than seven in 10 folks with employer-sponsored health insurance are satisfied with their plans. Nearly 60 percent of people say they oppose Medicare for All if it comes at the expense of private insurance, according to a recent Kaiser Family Foundation poll.

Expanding Medicare is a bad deal. Lawmakers should abandon the idea.

Sally C. Pipes (@sallypipes) is a contributor to the Washington Examiner's Beltway Confidential blog. She is president, CEO, and Thomas W. Smith Fellow in Health Care Policy at the Pacific Research Institute. Her latest book is The False Promise of Single-Payer Health Care (Encounter 2018).