“All the research shows the single most effective way to reduce abortion is contraception,” he said. “The problem with pro-life groups is all the solutions they promote to reduce the abortion rate, none of them moves it in a reliably positive direction. . . . The data show no reliable correlation between the degree of restrictions in a state and the abortion rate.”

Yet pro-life groups refuse to take up the cause of birth control, because so many of their supporters have problems with that, too. “They’ve betrayed the one thing they stand for, which is reducing abortions,” Saletan said.

A 2014 study by the Guttmacher Institute (an abortion-rights outfit but one whose research is cited by both sides) found that between 2008 and 2011 “a combination of increased contraceptive use and greater reliance on highly effective methods helped reduce overall levels of unintended pregnancy and subsequent abortion.” In particular, Guttmacher credits an increase in the use of “long-acting, reversible contraceptives” such as new-generation IUDs.

But antiabortion groups question this conclusion. Charmaine Yoest, who runs Americans United for Life, told me that “I haven’t seen anything” to convince her that more contraceptive use reduces abortion.