The Senate unanimously confirmed Leon E. Panetta as secretary of Defense on Tuesday, putting the Pentagon in the hands of a former Democratic congressman and budget expert amid growing political discontent over the cost and reach of President Obama's military engagements. Panetta, who spent two years as director of the Central Intelligence Agency, will replace Robert M. Gates, who is retiring after serving in two consecutive administrations. In a statement, Panetta thanked the Senate "for the strong vote of confidence" and said he was "deeply honored" by the 100-0 tally and the president's nomination. His confirmation comes as Obama is...