WASHINGTON — Sidney Blumenthal stood to benefit financially from his unofficial advice to Hillary Clinton on U.S. policy in Libya when Clinton was secretary of State, according to the Republican chairman of the House committee investigating the 2012 terrorist attacks in Benghazi. “Beyond the pure politics that were occurring at this time, perhaps more disturbing is that at the same time Blumenthal was pushing Secretary Clinton to war in Libya, he was privately pushing a business interest of his own in Libya that stood to profit from contracts with the new Libyan government — a government that would exist only...