Two days before the deadly Sept. 11 attack on Americans in Libya, three U.S. officials met pro-government militias working to provide security in the city of Benghazi. In that meeting, which included the American economic and political counselors, Mohammed el Gharabi, a leader of a prominent militia, says he warned the Americans that the security situation in Benghazi was deteriorating. Assassinations are becoming rampant; no one is safe, including militiamen like himself, he says he told the Americans. He asked for help to secure Benghazi and suggested scaling back or possibly closing diplomatic missions until conditions were more secure. He...