The American military faces a growing threat of potentially fatal equipment failure—and even foreign espionage—because of counterfeit computer components used in warplanes, ships, and communication networks. Fake microchips flow from unruly bazaars in rural China to dubious kitchen-table brokers in the U.S. and into complex weapons. Senior Pentagon officials publicly play down the danger, but government documents, as well as interviews with insiders, suggest possible connections between phony parts and breakdowns.