T WAS A SWELTERING DAY in the summer of 2004, and Eric McDavid, then 26 years old, was in Des Moines, Iowa, for an annual gathering of self-described anarchists.

McDavid had come from his parents' home outside Sacramento, train-hopping the 1,700-mile journey and scavenging for food where he could, including in dumpsters. An idealistic young man with a shaved head and a thick red beard, McDavid had been drawn to activism following the 9/11 terrorist attacks, when his parents gave him a copy of Michael Moore's book Dude, Where's My Country? McDavid began to attend protests in the San Francisco area, eventually gravitating toward anti-government views.

In Iowa, McDavid was staying with other activists in a farm house with a large porch.