Preet Bharara, the U.S. attorney for the Southern District of New York, made front-page news in December when he booked an obscure Indian diplomat—deputy consul general Devyani Khobragade—for underpaying her maid. The foreign policy headache from the arrest ended when Khobragade left the country, but the more serious domestic hazard remains: that of the expanding latitude of U.S. attorneys in battling crime, which too often results in unchecked power that jeopardizes the public good.