STURGIS, S.D. ? Volunteers pushing to overturn the nation’s most far-reaching abortion ban are surprised and delighted by the response as they circulate petitions to put the law up for a public vote.

Even in the most conservative corners of this conservative state, both Republicans and Democrats – including some voters who say they oppose abortion – are eagerly signing the petition. In two weeks, volunteers have collected a third of the signatures they need to get a November referendum on the ban.

Some voters dismiss the abortion-rights activists as out of touch with South Dakotan values. “People here have a sense of morals and ethics,” said Darcy Patterson, 40. “I don’t want to change the law.”

But many others say their legislators went too far when they voted last month to prohibit all abortions, even in cases of rape or incest, unless the mother’s life is at stake.

The law asserting that embryos have an “unalienable right to life” from the moment of conception is set to take effect July 1. Women will not face charges for ending pregnancies, but doctors who help them could get up to five years in prison. Even if they believe an abortion is necessary to save a woman’s life, physicians must do all they can to save the fetus.

The abortion ban passed overwhelmingly: 23-12 in the Senate and 50-18 in the House.

Supporters expected the measure to draw an immediate court challenge from Planned Parenthood, which operates the only clinic providing abortions in South Dakota. Abortion opponents wanted a legal fight that could lead the U.S. Supreme Court to overturn Roe v. Wade, the 1973 decision establishing a constitutional right to abortion.

But abortion-rights forces chose not to sue. Instead, they’re appealing directly to voters.

On college campuses, in tiny farm towns, in tanning salons, on golf courses and in city parks, more than 400 volunteers are circulating petitions. They are organized by the South Dakota Campaign for Healthy Families, which in turn is funded by major abortion-rights supporters such as Planned Parenthood, NARAL Pro-Choice America, and the American Civil Liberties Union.

Even opponents expect the campaign to easily collect the 17,000 valid signatures needed to put the referendum on the ballot. That would put the abortion law into legal limbo, on hold until the November election. If voters reject the law, it will be stricken from the books. If they uphold it, abortion-rights activists can still sue to block its enforcement.