THE United States didn’t set out to eradicate the Mandeans, one of the oldest, smallest and least understood of the many minorities in Iraq. This extinction in the making has simply been another unfortunate and entirely unintended consequence of our invasion of Iraq — though that will be of little comfort to the Mandeans, whose 2,000-year-old culture is in grave danger of disappearing from the face of the earth.

The Mandeans are the only surviving Gnostics from antiquity, cousins of the people who produced the Nag Hammadi writings like the Gospel of Thomas, a work that sheds invaluable light on the many ways in which Jesus was perceived in the early Christian period. The Mandeans have their own language (Mandaic, a form of Aramaic close to the dialect of the Babylonian Talmud), an impressive body of literature, and a treasury of cultural and religious traditions amassed over two millennia of living in the southern marshes of present-day Iraq and Iran.

Practitioners of a religion at least as old as Christianity, the Mandeans have witnessed the rise of Islam; the Mongol invasion; the arrival of Europeans, who mistakenly identified them as “Christians of St. John,” because of their veneration of John the Baptist; and, most recently, the oppressive regime of Saddam Hussein, who drained the marshes after the first gulf war, an ecological catastrophe equivalent to destroying the Everglades. They have withstood everything — until now.

Like their ancestors, contemporary Mandeans were able to survive as a community because of the delicate balance achieved among Iraq’s many peoples over centuries of cohabitation. But our reckless prosecution of the war destroyed this balance, and the Mandeans, whose pacifist religion prohibits them from carrying weapons even for self-defense, found themselves victims of kidnappings, extortion, rapes, beatings, murders and forced conversions carried out by radical Islamic groups and common criminals.