The chairman of a special House committee created to investigate the 2012 Benghazi tragedy on Monday instructed his staff to review secretly recorded tapes and intelligence reports that detail Hillary Rodham Clinton’s role in advocating and executing the war in Libya, opening the door for a possible expansion of his probe. Rep. Trey Gowdy’s decision to seek a review of the materials, first highlighted in a series of Washington Times stories last week, carries consequences for the 2016 election in which Mrs. Clinton is expected to seek the presidency. It could also move the committee to examine the strained relationship...