From CNN:

Before entering a high-threat area like Benghazi, or indeed any other unstable environment, it is essential to determine if the mission is worth the risk. In assessing Benghazi, the first question that comes to mind is:  What was so important about having a diplomatic presence in a city characterized as unstable; a city the British, French and United Nations had effectively abandoned because of warring militias and earlier bombings?  Why was the United States still there? All assessments about the viability of the mission and all plans to protect U.S. diplomatic compounds around the world have to begin with answers to this question.