WASHINGTON—In his first meeting with President Barack Obama, CIA crime and counternarcotics analyst Timothy R. McIntire haltingly explained to the nation's first African-American commander in chief the highly classified origin of crack cocaine and the resultant epidemic that swept across U.S. inner cities. "Well, you see, sir...thing is, we needed money to help those Contras back in '85, and we never really expected...so we distributed it, and...shortsighted...and, ha, well, Christ—is it hot...