I had a brief chat last week with the security officer for one of the United Nations program offices in Jerusalem, and it confirmed what I'd suspected from recent press reports. The UN Department of Safety and Security was thoroughly burned by the still-not-fully-released internal review of the circumstances surrounding the bomb attack on the UN headquarters building in Algiers last December, and the organization is expecting a further purge of the leadership. The UN/DSS Director had the grace to resign right after the attack, but his senior staff remains in place, at least for now.
The UN field security officers seem to be walking on eggshells today, since their leadership in New York has gotten excessively cautious and risk-averse. Unfortunately, an unwillingness on the part of Headquarters to tolerate any amount of risk is no more realistic or practical than the opposite extreme. Incidents like the Algiers bombing make a security bureaucracy gun-shy, and the effect usually persists for a few years before a sensible risk management attitude eventually emerges (if it ever does).