Eric Holder Jr., the nation's first black U.S. attorney general, is preparing to announce his resignation Thursday after a tumultuous tenure marked by civil rights advances, national security threats, reforms to the criminal justice system and five and a half years of fights with Republicans in Congress. Two sources familiar with the decision tell NPR that Holder, 63, intends to leave the Justice Department as soon as his successor is confirmed, a process that could run through 2014 and even into next year. A former U.S. government official says Holder has been increasingly "adamant" about his desire to leave soon...