A government-sponsored “public option” in the ACA’s marketplaces will not fix the health care system for two reasons.

First, a public option would leave today’s multiple payers in place, merely adding one more payer to our already fragmented system. It would thereby forgo at least four-fifths of the administrative savings available through a single payer. It would do nothing to streamline the administrative tasks (and costs) of hospitals, physician offices, and nursing homes, which would still contend with multiple payers and hence still need the complex cost-tracking and billing apparatus that drives up administrative costs.

Second, a quarter-century of experience with public/private competition in the Medicare program (traditional Medicare vs. private Medicare Advantage plans) demonstrates that the private insurers will not allow a level playing field. Despite strict regulation, private insurers have successfully cherry-picked healthier seniors and have exploited regional health spending differences to their advantage.

Thus, under the ACA, relying as it does on the participation of large, for-profit insurers, a public option would not lean toward single payer, but toward the segregation of patients, with profitable ones in private plans and the unprofitable ones concentrated in the public plan, dooming the latter to failure.

As for a “Medicare buy-in” that would lower the age of eligibility for Medicare to 55, for example, such a buy-in would only work if enrollment were mandatory. Otherwise it would become the place where all the sickest patients get dumped. That might be OK for the sick enrollees, since Medicare is better and more secure than private coverage, but it would drive total health care costs (and premiums) up, not down.

Our current “system” is structurally flawed; patching it up is not a real solution.