(Rogelio V. Solis/AP)

So far though, no personhood amendment has gotten very close to becoming law. Many don’t get enough signatures to land a ballot initiative, and those that do have failed by double-digit margins. But Carmon thinks that may change when Mississippi votes on a new personhood amendment, Initiative 26, next week. “In the most conservative state in the country, with an energized, church-mobilized grass roots, Mississippi could well be the first state to pass one,” she writes.

One key thing Carmon picked up on in her piece is the relatively fringe role the idea of personhood has played within the anti-abortion movement. I covered the personhood movement for Newsweek in 2008, when Colorado was the first-ever state to vote on such an amendment. The whole campaign was organized by an energetic 21-year-old named Kristi Burton. The anti-abortion establishment, however, was none too thrilled with it. Here’s what I wrote back then:

Burton has not received much support for Amendment 48 from her most natural allies—the country's major pro-life groups. Heavyweights like National Right to Life and Americans United for Life are not backing it. "There are other ways to protect human life that we focus on because we believe they are the most effective," says Clark Forsythe, president of Americans United for Life. Although pro-life leaders generally agree with Burton that life begins at fertilization, they fear a direct challenge to Roe v. Wade would ultimately be slapped down by the Supreme Court—still at least one vote shy of an anti-Roe majority—setting back the movement. "The established pro-life movement feels … we should stop trying to overturn Roe because the time isn't right," says Richard Thompson, president of the Thomas More Law Center, a conservative public-interest firm that has advised Amendment 48. "Then there is this huge grassroots movement saying it's immoral not to try and save innocent lives."

The Colorado ballot initiative went on to fail by a 40-point margin, but similar initiatives began popping up in other states. And when Carmon traveled to Mississippi, she found much greater enthusiasm for personhood activism, noting that some Democrats there had come to endorse it. Perhaps an even more telling sign of personhood tiptoeing into the mainstream is its recent endorsement by presidential contender Mitt Romney. He told told Fox News he would “absolutely” support a constitutional amendment defining life as beginning at conception.

Still, its hard to argue that personhood has become part of the mainstream anti-abortion agenda. Most major groups in the movement are still skittish about the strategy. When I attended the National Right to Life Committee’s state strategy conference this year, there was no mention of personhood: The group was more focused on late-term abortion bans and ending insurance coverage for the procedure. Americans United for Life, the country’s oldest anti-abortion group, provides states advocates with dozens of model laws to use in their legislatures. But it has not written a model law to define life as beginning at conception.

The Mississippi vote next week will be a key one to watch for the personhood movement. If it passes, it could very well draw a Supreme Court challenge on the issue while forcing anti-abortion advocates to figure out where it fits into their movement. But if a personhood amendment can’t pass in Mississippi, it could draw more questions about whether this could succeed anywhere.