Whereas the front line is thin and shaky, there is a security vacuum in Benghazi.
The Ethiopians say they are keen to go but do not want to leave a security vacuum.
The Americans are worried lest Mr Saleh's sudden exit creates a security vacuum.
He welcomed its continued existence in the south, saying its main objective should be to avoid a security vacuum.
Even so, the riots occurred at a time when Egypt was struggling with a security vacuum following Mubarak's ouster.
"Everybody agrees that we don't want a security vacuum in Kosovo, " Bacon said.
He has failed to fill a security vacuum, making his task of dealing with a growing economic crisis much harder.
"In particular, the task is to understand the nature of the new threat - more decentralised, more fragmented, taking advantage of the ungoverned spaces and security vacuum in parts of North Africa, " he said.
In the security vacuum and chaos people are increasingly turning to their tribes and their families to protect themselves, and sectarian violence has driven many people to have to move from one area to another area where their religious group predominates.
"Security in a vacuum is no security at all, if you are just maintaining the conditions that created the problems in the first place, " Roth said.
Unlike after the last election, however, a caretaker government is providing security and basic services and preventing a dangerous power vacuum from erupting.
WHITEHOUSE: Change of Command, End of Combat Operations Ceremony
Mr. Dodd's petulance has gone beyond the usual Beltway payback and is now creating a leadership vacuum damaging to U.S. national security.
Mr Mikati had been pushing for the extension of the mandate of the internal security chief, Ashraf Rifi, to avoid what he described as "a dangerous vacuum".
BBC: Lebanese PM Mikati's cabinet resigns amid growing crisis
In that vacuum, large, powerful Palestinian families have stepped in and hold increasing sway, especially over security matters.
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