Abortion opponents launched a petition drive to overturn Gov. Jennifer Granholm's veto of legislation that would restrict partial-birth abortions.

Right to Life of Michigan is spearheading the campaign. If coalition members can gather 254,206 signatures within 180 days, they can bring the Legal Birth Definition Act, which defines life as the moment when part of the fetus is expelled from a woman's body, back to the Legislature.

The Legislature passed the bill with an overwhelming majority last year. In the Senate, 25 of the 38 members supported the bill, and the House passed the bill, 74-28. Granholm vetoed the bill in October, saying it did not give exceptions to allow the procedure if the woman's life was at stake.

If enough petitions are gathered, the initiative would go before the Legislature, needing only a simple majority to pass without Granholm's approval.

"We will drain the ink from the governor's veto pen," said Barbara Listing, Right to Life of Michigan president, adding that more than 300,000 petitions are in circulation around the state.

The number of signatures needed for the overturn comes from the Michigan Constitution, which calls for 8 percent of the total votes cast for governor candidates.

Numerous senators and representatives, including Senate Majority Leader Ken Sikkema, joined members of state religious organizations in the campaign's launch at the Capitol on Thursday, wearing white buttons emblazoned with "The People's Override."

Sikkema expressed his frustration that Granholm's veto couldn't be overturned with a two-thirds majority of the Legislature, which was one vote short in the Senate.

"That would've been my preferred course of action," he said. "But this is the right thing to do."

Bill Ballenger, editor and publisher of Inside Michigan Politics, said he anticipates the initiative will gain the signatures and easily slide through Legislature.

"I think they're going to get the signatures, and I think it's going to pass in the majority," Ballenger said. "It's going to be enacted into law, and (Granholm) is not going to get a second bite at the apple."

Right to Life of Michigan has held two similar campaigns, and both were successful. In 1988, a petition initiative disallowed Medicaid from funding abortions. In 1990, a similar initiative overturned then-Gov. James Blanchard's veto of a bill requiring parental consent before a minor can have an abortion.

Granholm spokeswoman Liz Boyd said, even if the petitions are successful in overturning the veto, the courts will rule the legislation unconstitutional.

"If the petition being circulated fails to include a clear exception for the life and health of the mother, it will undoubtedly be struck down by the courts," she said.

Boyd declined any further comment on the issue.

The federal bill signed by President Bush in October banning partial-birth abortions was suspended while it faces challenges in courts.

According to the Planned Parenthood Advocates of Michigan, about nine of the more than 29,000 abortions performed in the state were partial-birth.

Pro-choice advocates opposing the bill say it is a step in restricting reproductive rights for women.

Tara May can be reached at maytara@msu.edu.