John Calfee on the dangers of a "public plan" for health insurance:

a public plan would possess formidable and perhaps overwhelming competitive advantages -- generated not by efficiency but by the artificial advantages of "public" status. This would have two disastrous consequences. The first will be to cause most Americans now covered by private insurance to move to public insurance -- one step away from single-payer health care. The second will be to undermine incentives to develop more of the immensely valuable medical technology that is central to all of health care.

Gregory Mankiw evaluates the risk of a public health care plan.

Even if one accepts the president's broader goals of wider access to health care and cost containment, his economic logic regarding the public option is hard to follow. Consumer choice and honest competition are indeed the foundation of a successful market system, but they are usually achieved without a public provider. We don't need government-run grocery stores or government-run gas stations to ensure that Americans can buy food and fuel at reasonable prices.

An important question about any public provider of health insurance is whether it would have access to taxpayer funds. If not, the public plan would have to stand on its own financially, as private plans do, covering all expenses with premiums from those who signed up for it.

But if such a plan were desirable and feasible, nothing would stop someone from setting it up right now. In essence, a public plan without taxpayer support would be yet another nonprofit company offering health insurance. The fundamental viability of the enterprise does not depend on whether the employees are called "nonprofit administrators" or "civil servants."

In practice, however, if a public option is available, it will probably enjoy taxpayer subsidies. Indeed, even if the initial legislation rejected them, such subsidies would be hard to avoid in the long run. . . .

Such explicit or implicit subsidies would prevent a public plan from providing honest competition for private suppliers of health insurance. Instead, the public plan would likely undercut private firms and get an undue share of the market.

President Obama might not be disappointed if that turned out to be the case. During the presidential campaign, he said, "If I were designing a system from scratch, I would probably go ahead with a single-payer system."