People at a pro-life rally in Santa Fe, N.M., release 400 balloons on Jan. 18, 2012, to represent the estimated 400 abortions that occur in New Mexico every month

Correction appended, Nov. 18.

Students leaving afternoon classes at the University of New Mexico last Thursday were greeted with a raucous spectacle: abortion protesters had flooded the campus, passing out flyers and occasionally yelling slurs from across the quad. Near the school entrance, a gaggle of teens calling themselves the Survivors of the Abortion Holocaust brandished a huge image of a dismembered, fully developed fetus. Ten feet away, pro-choice advocates handed out free pizza and abortion testimonials to interested classmates.

Outside the library, notorious pro-life protester Rives Grogan, who was banned from Washington, D.C., last year after lodging himself in a tree during President Obama’s Inauguration, was taken into custody for screaming at students and faculty.

This circus has become familiar in Albuquerque, where city residents will vote Tuesday on the nation’s first-ever municipal referendum to ban abortions after 20 weeks. The vote — which would effectively end late-term abortions in New Mexico — has turned this low-key, progressive city of a half million people into the latest flash point in the abortion culture wars. It opens a new pro-life strategy to push abortion restrictions at the local as well as state and federal levels.

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“I would be surprised if what’s happening in Albuquerque didn’t start to replicate itself in other places,” said Marjorie Dannenfelser, president of the Susan B. Anthony List, a national pro-life organization that has been involved in the ballot initiative and has pushed for a similar ban at the federal level.

Titled the Pain-Capable Unborn Child Protection Ordinance, the initiative would prevent women in the city from obtaining an abortion after five months of pregnancy, with a narrow exception for cases when a woman’s life is in immediate danger.

Based on the disputed claim that a fetus can feel pain at 20 weeks, late-term-abortion bans target the small number of abortions performed after that point — 1.5% of U.S. abortions, according to the Guttmacher Institute, a reproductive-health think tank. Thirteen states have passed late-term-abortion bans, although judges have struck down those laws in Idaho and New Mexico’s neighbor Arizona. A federal 20-week abortion ban passed the House of Representatives in June, and Republican Senator Lindsey Graham, of South Carolina, introduced a 20-week ban bill in the Senate earlier this month.

Albuquerque, called by antiabortion activists “the late-term-abortion capital of the country,” is a natural testing ground for the nation’s first municipal abortion restrictions. Following the murder of late-term-abortion doctor George Tiller in 2009, two of the physicians from his clinic in Wichita, Kans., moved to Albuquerque to practice at Southwestern Women’s Options, making it one of only a few clinics the country that offer abortions after the sixth month of pregnancy, and one of just two clinics in New Mexico that perform the procedure after 20 weeks.

In 2010, pro-life activists Tara and Bud Shaver, who had trained with the Wichita-based antiabortion group Operation Rescue, moved to Albuquerque with the express goal of shutting down Southwestern Women’s Options. Since then, the couple has engaged in what Tara Shaver calls “prayerful witness” at the clinic, launching investigations into the clinic’s doctors and routinely circling the practice in a “Truth Truck” emblazoned with images of a dismembered fetus.

While these efforts failed to close down the clinic, the Shavers’ aggressive activism galvanized the local pro-life community and drew attention to the lack of a gestational limit on abortion in New Mexico. “Whenever we tell people abortion is legal for all nine months, they argue that no one ever does it that late in a pregnancy,'” Tara Shaver said. “They do, and they are coming to Albuquerque to do it.”

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After attempts to pass state abortion restrictions repeatedly languished in New Mexico’s Democratic-controlled legislature, pro-life groups teamed up with the Shavers this past summer to petition for a citywide late-term-abortion ban in Albuquerque, where the city charter allows citizens to file ballot initiatives as long as 12,091 signatures are gathered. What began as a local effort has morphed into a million-dollar campaign, with national groups on both sides of the abortion issue pouring hundreds of thousands of dollars into advertisements and get-out-the-vote initiatives.

At least six antiabortion groups have campaigned to support the ban, including the Susan B. Anthony List, which spent $176,000 on the Albuquerque campaign in the six weeks leading up to the vote. To thwart these efforts, a coalition of liberal groups, including Planned Parenthood and the American Civil Liberties Union of New Mexico, have banded together under the banner Respect ABQ Women.

With an assist from Organizing for Action, the grassroots fundraising machine spun out of Obama’s presidential campaign, Respect ABQ Women has raised $680,000 to defeat the ordinance, in the hopes of deterring other antiabortion groups from pursuing a similar strategy in other parts of the country.

“Albuquerque voters are carrying a lot of responsibility,” said Micaela Cadena, policy director for Young Women United, a reproductive-justice group working with Respect ABQ Women. “Not only are we voting for our own lives and families, we’re voting for residents from across the state who come to the city for care. But also across the country as well, it’s important that we show the opposition here and now.”

A record number of voters have already turned out for the Albuquerque referendum, with more than 35,000 people casting ballots as of Friday. Both sides expect that the final tally will be close.

“This is a new strategy — no one has ever tried this at a municipal level,” said Patrick Davis, director of ProgressNow New Mexico. “The bottom line is we don’t know how this is going to go.”

While the fate of Albuquerque’s referendum remains uncertain, the strategy is already drawing interest from pro-life groups in other cities. Last week, pro-life activists in New Mexico’s Valencia County, south of Albuquerque, asked county commissioners to consider adopting a similar ban on late-term abortions. And regardless of the outcome on Tuesday, Davis believes that antiabortion activists will use the city’s ordinance as a template for similar municipal abortion restrictions. “If it fails, other places will still have a model for how this works,” he said. “No matter what happens, they will have a better strategy going out of this.”

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Correction: An earlier version of this story stated that a pro-choice group Respect ABQ Women had raised more than $68,000. The correct figure is $680,000, according to financial disclosures filed with the City of Albuquerque as of Nov. 8.