President Obama has repeatedly promised that if you like your private health insurance, you can keep it. Unfortunately, the economic incentives hard-wired into his health plan would make that virtually impossible.

Obama and congressional Democrats want to force employers (who handle health insurance for most working Americans) to offer a federally approved set of health benefits. Otherwise, they'd have to pay some sort of payroll tax to finance coverage in a government-run health plan.

Many employers would naturally opt to forgo the hassle and expense of trying to provide coverage. They'll simply pay the tax and dump their employees into the government plan — never mind what their employees want.

How many Americans would lose their private coverage? Economists predict that if Congress creates a new government health plan, complete with taxpayer subsidies, artificially low premiums and co-payments and artificially low payments to doctors and hospitals (like Medicare payments), that millions would be dropped into the government plan. The Lewin Group, the nation's leading econometrics firm specializing in health care, estimates that anywhere from 12 million to 119 million Americans would find themselves in the new government plan.

Millions of Americans losing private coverage isn't a pleasant prospect. Not surprisingly, moderate Democrats on Capitol Hill are staking out their firm opposition to such a proposal. So the administration's allies in Congress are trying to dress it up to make it appear less frightening.

For example, Sen. Charles Schumer, D-N.Y., has offered a "compromise" government-run health plan that would require that the public plan and the private plan abide by the same rules and regulations and compete on a "level playing field." Under Schumer's proposal, the new government plan wouldn't get special government tax revenues or appropriations. It would have to pay doctors and hospitals "more" than what Medicare pays. It wouldn't force doctors or hospitals to sign up. The government officials who manage the public plan would be different from those who set the rules for competition, and it would have a reserve fund to pay claims, just like private health insurance.

Which poses an obvious question: If all plans operate under the same rules, why would Congress need to create a special public plan? But as Robert Pear, veteran health reporter for the New York Times, observed recently, Schumer's "compromise" raises many other unanswered questions about how, exactly, the new government-run plan would compete with private health insurance on a level playing field.

Understand that a new government-run health plan would be a wholly owned subsidiary of the Congress. Lawmakers would create it, and, at least initially, would fund it. To create a "level playing field" for its plan and private health plans against which it would compete, Congress would have to do much more than what Schumer is prescribing. No special advantages, right?

So, the new government-run health plan would have to observe the same state laws and regulations — including state-mandated benefits and state premium taxes and solvency requirements — that apply to private health plans in the states where it competes for business. Officials in the new government plan would follow the same state and federal tort and contract laws as private health plan officials; i.e., they could be sued for breach of contracts or damages. No special protections, right?

The new government-run health plan would be subject to the same accounting standards, including the accounting standards for unfunded and other liabilities, as private health plans. Officials in the new government plan would have to negotiate rates and benefits in the private market, set up provider networks, and pay doctors and hospitals at the rates determined in the competitive market. No coercion or government price fixing, right?

The list goes on, but you get the idea.

Maybe you can imagine Congress actually agreeing to all of these conditions, and more, to create a "level playing field" for its new government health plan to compete with private health plans. Maybe the congressional champions of a new government plan are sincere, and have no desire to destroy your private health insurance and leave you with no options.

But on a level playing field, some businesses fail. So would the new government health plan be allowed to become insolvent? Will it be allowed to fail? Or will it become another candidate for an eternal taxpayer bailout?

You get one guess.

Robert E. Moffit is the director of the Center for Health Policy Studies at the Heritage Foundation in Washington, D.C.