After denouncing Paul Ryan’s premium support Medicare reform as “right-wing social engineering” in May, Mr. Gingrich now says he supports it as long as it is only voluntary. As with Social Security, people could continue to receive today’s unreformed, open-ended benefits if they preferred. This model may be politically safer and perhaps more saleable to voters, but it also does little to improve the status quo. Why would anyone leave the all-you-can-eat buffet without an incentive to choose cost-conscious options?

Mitt Romney also says he’ll leave fee-for-service Medicare untouched, but the key difference is that under his plan all seniors would receive the same defined contribution. They’d pay the marginal cost above this fixed subsidy, increasing competition for the health-care dollar among insurers and hospitals, doctors and other providers.

Mr. Gingrich’s plan is merely a gloss on Medicare Advantage, which has done some modest good as one out of four beneficiaries have moved to private options but without turning the fiscal battleship. At least on Medicare, Mr. Romney is the bolder reformer.