ON ABORTION, most mainstream Republicans adhere to variants on a theme: They oppose abortion, but add that the country is not ready to ban it, that other issues matter more and that Republicans should focus on building a big tent so that they can recapture the White House.

Recently, however, Sen. John McCain has strayed from this formula. He says he is pro-life, but then unleashes a powerful argument in favor of Roe v. Wade, the Supreme Court decision that legalized abortion. "In the short term, or even the long term," he told the San Francisco Chronicle, "I would not support repeal of Roe v. Wade, which would then force X number of women in America to [undergo] illegal and dangerous operations."

It may seem a touch eccentric for Mr. McCain to be arguing against his own views, but there is actually something refreshing about it. Mr. McCain's rivals for the Republican presidential nomination profess to regard abortion as immoral, akin to infanticide. But if this is their view, it is hard to see how they can avoid making the reversal of Roe v. Wade a key policy goal, or how they can argue that other issues are more pressing. By seeking to put abortion to one side, Republicans implicitly acknowledge that the subject is morally complex and that respectable arguments can be made for leaving abortion choice to women. Mr. McCain is frank enough to make one of those arguments explicitly.

What's more, the argument that he chose is a good one: A ban on abortions would lead to illegal abortions. Before the Roe decision in 1973, thousands of American women died after grimy operations in back-alley clinics, and many more thousands were left sterile. The World Bank estimates that, around the world, 125,000 to 200,000 women die annually of complications from botched abortions, many performed where they are not allowed.

Abortion always will be an agonizing moral issue. Politicians who sincerely believe that it is the equivalent of murder ought to say so and ought to make the issue a priority. But those who want to emphasize other things need to acknowledge the logic of their position. They are saying, effectively, that abortion is too murky a subject for politicians to resolve. And that is precisely why women should be left to resolve it, privately.