In the health-care debate, the "public plan" is all things to all people. For supporters, it would discipline greedy private insurers and make health-care coverage affordable. For detractors, it's a way station on the path to a single-payer insurance system of government-run health care. In reality, the public plan, also known as the public option, is mostly an exercise in political avoidance: It pretends to control costs and improve access to quality care when it doesn't.

As originally conceived by Yale political scientist Jacob Hacker, the public plan would be a government-created, nonprofit insurance company providing Medicare-like coverage to the under-65 population. But unlike Medicare, benefits would be paid for mainly by premiums—not taxes. Americans could buy coverage from the public plan or a private insurer. (Click here to follow Robert Samuelson)

Competition and choice would increase, say liberals. Facing the low-cost public plan, private insurers would hold down their own premiums, the argument goes. Health-care costs for everyone would moderate. Government subsidies to provide universal coverage would be cheaper. By some estimates, Medicare's administrative costs are only 3 percent of spending, compared with 13 percent or more for private insurers. A new public plan is widely presumed to enjoy an advantage in overhead.

Nonsense, retort critics. The public plan's low costs would be artificial. Its main advantage would be the congressionally mandated requirement that hospitals and doctors be reimbursed at rates at or near Medicare's. These are as much as 30 percent lower than rates paid by private insurers, says the health-care consulting firm Lewin Group. With such savings, the public plan could charge much lower premiums and attract lots of customers. But health costs wouldn't subside; hospitals and doctors would offset the public plan's artificially low reimbursements by raising fees to private insurers, as already occurs with Medicare. Premiums would increase because private insurers must cover costs to survive.

As for administrative expenses, any advantage for the public plan is exaggerated, say critics. Part of the gap between private insurers and Medicare is statistical illusion: Because Medicare recipients have higher average health expenses ($10,003 in 2007) than the under-65 population ($3,946), its administrative costs are a smaller share of total spending. The public plan, with younger members, wouldn't enjoy this advantage.

Likewise, Medicare has low marketing costs because it's a monopoly. But a non-monopoly public plan would have to sell itself and would incur higher marketing costs. Private insurers' profits (included in administrative costs) also explain some of Medicare's cost advantage. But profits represent only 3 percent of the insurance industry's revenue. Moreover, accounting comparisons are misleading when they don't include the cost of Medicare's government-supplied investment capital. A public plan would also need investment capital. And suppose the public plan suffers losses. Congress would assuredly bail it out.

The promise of the public plan is a mirage. Its political brilliance is to use free-market rhetoric (more "choice" and "competition") to expand government power. But why would a plan tied to Medicare control health spending, when Medicare hasn't? From 1970 to 2007, Medicare spending per beneficiary rose 9.2 percent annually compared to the 10.4 percent of private insurers—and the small difference partly reflects cost shifting. Congress periodically improves Medicare benefits, and there's a limit to how much squeezing reimbursement rates can check costs. Doctors and hospitals already complain that low payments limit services or discourage physicians from taking Medicare patients.

Even Hacker concedes that without reimbursement rates close to Medicare's, the public plan would founder. If it had to "negotiate rates directly with providers"—do what private insurers do—the public plan could have "a very hard time" making inroads, he writes. Hacker opposes such weakened versions of the public plan.

By contrast, a favored public plan would probably doom today's private insurance. Although some congressional proposals limit enrollment eligibility in the public plan, pressures to liberalize would be overwhelming. Why should only some under-65 Americans enjoy lower premiums? In one study that assumed widespread eligibility, the Lewin Group estimated that 103 million people—half the number with private insurance—would switch to the public plan. Private insurance might become a specialty product.

Many would say: Whoopee! Get rid of the sinister insurers. Bring on a single-payer system. But if that's the agenda, why not debate it directly? It's not insurers that cause high health costs; they're simply the middlemen. It's the fragmented delivery system and open-ended reimbursement. Would strict regulation of doctors, hospitals and patients under a single-payer system provide control? Or would genuine competition among health plans over price and quality work better?

That's the debate we need, but in truth, doctors, hospitals and patients don't want to be limited, whether by government or markets. Congress reflects public opinion. Fearing a real debate, we fake it.

Robert Samuelson is also the author of The Great Inflation and Its Aftermath: The Past and Future of American Affluence and Untruth: Why the Conventional Wisdom Is (Almost Always) Wrong .

© 2009