The commentators are agonising over the legal terms of UNSC 1973, which underpins the terms of the UN intervention in Libya.
Jonathan Freedland in the Guardian argues that the Allies should stop when Gaddafi's forces should not be attacked unless they are actively threatening the people.
This is a recipe for Gaddafi to play a cat and mouse game, stopping until the Allies stand down, then starting again, provoking more Allied action, then stopping, over and over. This is clearly impractical, but consistent with a literal reading of 1973.
Clearly, the intent of the resolution is to stop all threat to the Libyan population. If Gaddafi were to be left in power over Libya, the people would be at risk from his revenge. If Libya should be partitioned, the revolutionaries in his Western portion would suffer.
Therefore the intent of 1973 will only be implemented if Gaddafi leaves Libya. Which means that the Allies must enable the revolutionaries to win.
One powerful tool to this end that has not yet been deployed is for us to block Gaddafi's TV transmission.
The second is to facilitate the exile of Gaddafi, his family and friends to Uganda or somewhere.
Unfortunately, the third tool is to give arms (specifically, anti-tank missiles) to the rebels. This sticks in my craw, but it follows logically from the general argument, that Gaddafi must go.