ALBUQUERQUE — At the New Mexico Holocaust and Intolerance Museum, three dozen people, many of them teenagers, arrived last month without warning.

Wearing T-shirts that said “Survivors of the Abortion Holocaust,” they demanded that the museum include an exhibit on what they called the “American genocide” of legal abortion, and fanned out to scatter cards with pictures of bloody “late-term abortion victims.”

They then moved outside to picket with a banner calling Albuquerque “America’s Auschwitz.”

Albuquerque has become the latest flash point in the abortion wars, with Operation Rescue, the militant group based in Kansas, calling it the “late-term abortion capital of the country.” This is because a private clinic, Southwestern Women’s Options, is one of only a few nationwide that offers abortions after the sixth month of pregnancy.

A pitched political battle is now under way. After failed attempts in the Democratic-controlled Legislature, abortion opponents have collected enough signatures to hold a referendum over whether to make Albuquerque the first city in the country to ban abortions at 20 weeks after conception, just as a dozen states have done.