The rival sides in South Dakota’s historic vote on abortion each are claiming their position protects women’s health – an old argument on the abortion rights side but a new campaign tactic for anti-abortion advocates that has significantly changed the debate.

At stake is a South Dakota law passed earlier this year that would ban virtually all abortions. Voters will decide Tuesday whether to reject this toughest-in-the-nation ban or uphold it, likely triggering a lawsuit that could lead to the U.S. Supreme Court.

The vote also will serve as a barometer, watched by activists nationwide, gauging the effectiveness of the distinctive pro-ban strategy. Rather than stressing a fetus’ right to live or vilifying abortion providers, the Vote Yes For Life campaign has focused on depicting abortion as psychologically harmful to women.

“Support Women’s Health,” says the campaign Web site. Its ads feature women detailing their post-abortion despair.

The South Dakota Campaign for Healthy Families, which opposes the abortion ban, leads in the polls but still has found the strategy challenging to counter. It says there is no scientific evidence of pervasive psychological or medical problems among women who had abortions.

“The marketing is ingenious on their part,” said Dr. Maria Bell, a Sioux Falls gynecological oncologist who opposes the ban in part because she feels it jeopardizes women’s health. It would allow abortions only to save a woman’s life, with no exceptions for other health factors or cases of rape or incest.

“‘Abortion hurts women’ – that’s a great slogan, but they don’t have the data to back that up,” Bell said. “They have a lot of stories, but we don’t make public policies on anecdotal evidence.”

The chief of the pro-ban campaign, Leslee Unruh, talks often of regrets over an abortion she had, and says “the time has passed for any other strategy” by the anti-abortion movement.

She expresses annoyance at anti-abortion militants, some from out-of-state, who use more strident tactics, such as harassing women at the state’s one abortion clinic. “It can’t be someone on my side,” she said.

Abortion-rights activists acknowledge that some women struggle emotionally after abortions, but say most do not. “There’s no denying there are women who have painful reactions,” said Susan Cohen, of the Guttmacher Institute, which supports abortion rights. “That doesn’t invalidate the opposite feeling millions of women have, of relief at being able to move on with their lives.”

Cohen noted that roughly one-third of American woman have an abortion.

“If abortion were so harmful, we’d see a mass epidemic of women with severe mental health problems,” she said. “But there is no such mass problem.”