At least five of the proposals have failed, and others face legal challenges. However, a proposal to ban most abortions already has made South Dakota's ballot, and several of the other measures could ultimately advance - including two in the potential swing state of Colorado.
The pending measures are the product of two separate multistate campaigns, one mounted by anti-abortion activists who want to define human life as beginning at fertilization, and the other led by California businessman/activist Ward Connerly, who opposes affirmative action programs based on race and gender.
Connerly has prevailed three times in past elections, with voters in California, Michigan and Washington approving proposals banning government-sponsored race and gender preferences in public education, state hiring and public contracts.
Connerly targeted five states with similar measures this year, but the campaign already has suffered two defeats - conceding that too few signatures would be gathered by the deadline in Missouri, and bowing out in Oklahoma in the face of challenges to the signatures gathered there.
Connerly blames harassment and political conniving for the setbacks; his critics contend the petition campaigns were rife with fraud and deception.
Signature-gathering is in progress for Connerly's measures in Nebraska and Arizona. His allies already have submitted more than enough signatures in Colorado, although opponents have challenged nearly 69,000 of them.
Connerly, who is of mixed racial background, contends that the historic Democratic presidential race between Hillary Rodham Clinton and Barack Obama proves his contention that racial and gender preferences are no longer justifiable public policy.
"The argument for it is that society is racist and sexist, and that argument is totally collapsing," Connerly said. "We should go to socio-economic affirmative action ... but don't put race into the equation."
Supporters of the so-called Human Life Amendment - which would define "personhood" as beginning with fertilization - initially targeted four states this year. But the proposal failed to clear a legislative committee in Georgia and was rejected on technical grounds by state officials in Oregon.
On Tuesday, however, backers of the proposal in Colorado announced they had gathered well over the required number of signatures to get it on the November ballot. Signature-gathering for a similar measure is under way in Montana.
The anti-abortion community is divided over the measures, partly on strategic grounds. The National Right to Life Committee has not endorsed them, nor have Roman Catholic leaders in Colorado and Montana.
Supporters embrace the measures as a frontal assault on Roe v. Wade, the 1973 Supreme Court ruling that established a nationwide right to abortion. They expect any voter-approved Human Life Amendment to be challenged by abortion-rights backers, triggering a legal battle that might lead to the Supreme Court.
"We think this is the best vehicle to challenge Roe," said Brian Rooney, an attorney with the Michigan-based Thomas More Law Center, which helped draft the proposed amendments.
"Some people who are pro-life don't think the Supreme Court is of the mind to overturn it," Rooney added. "We say you'll never know until you ask."
Opponents say the proposals could have far-reaching impact if they became law, including the banning of some forms of birth control. Nancy Keenan, head of NARAL Pro-Choice America, said the measures were "far out of the mainstream" and were being pushed in part to re-energize "depressed and deflated" conservative voters.
"But we take these very seriously," Keenan said. "It takes time and money to run a campaign to defeat them."
An unrelated anti-abortion measure was pushed hard in Missouri before its backers abandoned it following a lawsuit by Planned Parenthood. The measure would have made abortion an act of "medical negligence" unless the woman was first evaluated for risk factors.
In California, anti-abortion forces are trying to place on the ballot a proposal requiring parental notification before a minor can obtain an abortion. California voters have twice rejected similar measures.
In South Dakota, voters two years ago rejected a measure that would have banned all abortions except to save a mother's life. Abortion foes are trying again this year, placing on the ballot another broad ban with exceptions in cases of rape, incest and serious health threat to the mother.
Beyond abortion and affirmative action, there are several other potentially volatile ballot measures.
Already qualified for Florida's ballot is a proposed state constitutional amendment outlawing same-sex marriage. Arizona legislators may place a similar measure on the ballot there, and gay-marriage opponents in California say they have submitted enough signatures to do likewise.
California's situation is noteworthy because the state Supreme Court is scheduled to rule Thursday on gay marriage. If it approves same-sex unions, a ballot measure in November would provide voters a chance to affirm or overturn that ruling.
In Arkansas, conservatives are gathering signatures for measure aimed at banning gay people from adopting or being foster parents. Another Arkansas measure would require government agencies to verify all those seeking public benefits are legal U.S. residents.
Two years ago, left-of-center groups tried to counter the conservatives' ballot-measure tactics by successfully pushing proposals in several states to raise the minimum wage. There is no such coordinated effort this year, in part because liberal forces feel optimistic about their overall election prospects.
"The right wing is organizing around same old bag of tricks on social issues, but I don't think they'll deliver as much as they expect," said Kristina Wilfore of the liberal Ballot Initiative Strategy Center. "We're not as desperate as the other side to change the conversation."