Mr. Pack is a researcher of Middle Eastern History at the University of Cambridge. He is president of Libya-Analysis.com. Mrs. Khalil is an associate professor at CUNY. She is currently traveling in Libya while on a Fulbright Scholarship to Tunisia.

Sept. 11 is now a date that signifies a national tragedy for Libya as well as the United States. The attack on the U.S. diplomatic mission in Benghazi that killed four Americans, including Ambassador Christopher Stevens, has upset the delicate political transition from dictatorship to democracy that was unfolding here. It also has obscured parliament's prudent selection Wednesday of Mustafa Abushagour—a moderate Islamist and respected technocrat—as prime minister. Yet spontaneous street demonstrations throughout the week denouncing the attack and seeking to pressure the government to act against its perpetrators suggest that Libyans are determined to build an inclusive society, free from fear....

On Wednesday night in Tree Square in Benghazi, we witnessed crowds expressing heartfelt disappointment, shouting slogans like, "Free Libya, terrorists out!" On Saturday, Libyan President Mohamed Magariaf told "NBC Nightly News" that non-Libyans were among those involved. The assertion dovetails with educated opinion here that the attack on the mission must have been planned by an al Qaeda affiliate in revenge for the U.S. drone killing of the Libyan-born al Qaeda leader Abu Yahya al-Libi in Pakistan in June. Few demonstrators we talked to knew about the alleged justification for storming the consulate—the hateful 13-minute YouTube video "The Innocence of Muslims." Among those who did, a minority incorrectly assumed that if the video was produced in the U.S., it must represent American public opinion or tacit government policy....