Army Gen. Stanley McChrystal's much-discussed prescription for building Afghanistan's army and police reflects in large part the recommendations of a previously unreported memo from the former U.S. general in charge of building Iraq's security forces, but the two documents show a differing approach to the role the Afghan National Police should play in the counterinsurgency campaign there. Retired Army Lt. Gen. James Dubik, who commanded Multi-National Security Transition Command-Iraq from June 2007 to September 2008, visited Afghanistan between July 8...