When Gen. John Campbell, the Army’s vice chief of staff, appeared last year at a budget hearing on Capitol Hill, he cited his son’s experiences as a soldier in Afghanistan to answer a senator’s tough questions about a troubled intelligence technology system. This week, after an inquiry by The Associated Press, the Army acknowledged that Campbell misspoke about his son’s unit, omitting some key facts as he sought to defend a $4 billion system that critics say has not worked as promised. Campbell faces another Senate hearing Thursday morning, this one on his nomination to lead U.S. forces in Afghanistan....