Abortion opponents are pushing ballot measures in five states this year. But the campaigns show as much division as unity in the antiabortion movement.

In California, an initiative would add that state to the long list that currently requires doctors to notify parents before giving abortions to minors. In Missouri, abortion foes are trying to require psychological examination to show the woman isn’t acting under duress. State officials say the law as written would be tantamount to a ban, but advocates dispute that.

In South Dakota, activists have revived a measure defeated two years ago that directly outlaws abortion. They have modified the proposal to try to boost support, adding new exceptions for the health of the mother and cases of rape or incest. In Colorado and Montana, abortion opponents are taking a newly popular tack, promoting constitutional amendments that give legal rights to human embryos.

Behind the varying measures is a philosophical split among antiabortion groups. Some want to promote measures that ban abortion outright, directly challenging the U.S. Supreme Court’s 1973 Roe v. Wade decision, which legalized abortion. Others prefer to chip away at abortion rights by limiting the types of procedures allowed, or finding other ways to limit access.

The moves in South Dakota, Colorado and Montana take a direct approach. The California proposal embraces the more modest strategy.

The incremental approach has had some success, such as a federal ban on a procedure called dilation and extraction or “partial-birth abortion.” That ban was upheld by the Supreme Court last year, but critics in the antiabortion movement argue that and similar changes only make abortions more acceptable to the public. That has reinvigorated some activists to try novel ways to challenge basic abortion rights, such as the ballot measures this year giving legal rights to embryos.

No such law exists in any state. But if enacted, a state constitutional amendment bestowing personhood rights at conception could lead to lawsuits challenging not only abortion but also in vitro fertilization, embryonic-stem-cell research and some forms of birth control.

While a direct abortion ban would be illegal under Roe, changing the definition of personhood could undercut the legal argument behind that ruling, proponents argue. Justice Harry Blackmun wrote for the court in Roe that if a fetus were defined as a person by law, the case “collapses” because the due-process protections of the 14th Amendment would have to be taken into account.

Some more established antiabortion groups such as the National Right to Life Committee and Focus on the Family haven’t gotten behind these initiatives. The top lawyer for the National Right to Life Committee has said that they could backfire because the Supreme Court would likely reject these challenges to Roe—and that an unfavorable ruling could make the job of overturning precedent even more difficult later.

Those concerns haven’t stopped grass-roots activists. The Colorado initiative, which is only one sentence long, is promoted by a 20-year-old named Kristi Burton, a student of an online law school. Churches around the state have flocked to her cause, helping to raise most of the 76,000 signatures needed for a May deadline.

“They heard about us and said that’s something I can believe in,” Ms. Burton said.

A personhood initiative is facing similar disputes among abortion foes in Montana. In a statement, the Montana Catholic Conference wrote of the measure, known as Constitutional Initiative 100 in that state: “We encourage any and all efforts to eliminate or reduce attacks on the unborn but do not believe CI-100 is the most beneficial venue to pursue necessary change.” The statement goes on to advocate for pregnancy-care centers, promotion of adoption and requiring judges to approve abortions for minors.

Backers of the South Dakota abortion ban say they are including exceptions for a mother’s health and for pregnancy by rape or incest to undercut arguments that led to the measure’s defeat two years ago. I learned a lot. This time we’re ready,” says Leslee Unruh, who spearheaded the current initiative and the previous attempt.

But Ms. Unruh’s modifications have cost her support from South Dakota Right to Life, which has said it can’t support the initiative because it doesn’t ban abortions in all cases.

In California, an initiative that would require doctors to get parental notification two days before giving an abortion to a minor is on the ballot for a third time after two defeats. Organizers said they turned in the last of more than 1.1 million signatures by Friday’s deadline. More than 30 states already have parental-consent or notifications laws.

The latest attempt at passage includes changes that allow certain family members to be notified in lieu of parents who have been found to be abusive. Supporters of the measure are framing it as a parents-rights issue, but opponents say that the law is onerous because of the two-day waiting period and because it allows parents to sue doctors.

“California is the most prochoice state in the country,” said Amy Everitt, state director of NARAL Pro-Choice California. “Every time they bring it up they lose by a larger margin.”

Nonetheless, the state’s abortion-rights advocates have spent heavily to fight the measures: $2.1 million in 2005 and $5.3 million in 2006.