Keep this in mind when it is brought up in the debate tonight.  According to State Department officials involved, the security requests were for the U.S. Embassy in the capital, Tripoli, not Benghazi, the New York Times reported last week:

In a stream of diplomatic cables, embassy security officers warned their superiors at the State Department of a worsening threat from Islamic extremists, and requested that the teams of military personnel and State Department security guards who were already on duty be kept in service.

The requests were denied, but they were largely focused on extending the tours of security guards at the American Embassy in Tripoli — not at the diplomatic compound in Benghazi, 400 miles away. And State Department officials testified this week during a hearing by the House Oversight and Government Reform Committee that extending the tour of additional guards — a 16-member military security team — through mid-September would not have changed the bloody outcome because they were based in Tripoli, not Benghazi.