There is increasing talk of this escalation over the Libya crisis. Certainly it makes military sense to have a plan ready and move suitable carrier borne and land based aircraft and other assets into position in case such a move becomes necessary. It may also have a deterrent effect on Gaddafi, if he knows (or at least his sons) that the international community will not allow massacres, from the air, of protesters. Gaddafi claims everybody loves him, the violence is organised by Bin Laden and anyway everything is peaceful. Diplomats and generals find themselves assessing a situation which is part real and part make believe.
There are, however, many caveats concerning a no fly zone, which make it mostly a bad idea. The first is that under no circumstances must it be another Anglo-American dominated military action. It must be multi-national. That will be difficult. The unanimity which has made the response to the situation in Libya, both in Europe and in the U.N., so strong might well break down, with Russia and China either abstaining or voting against. That would strengthen Gaddafi.
Next Gaddaffi is isolated with probably only a minority now willing to rally under his green flag. An American led (as it would be) hostile act over the skies of their country would prove a powerful emotional pull to rally together to its defence. Not all would join, but enough perhaps to keep the Gaddafi family going for several more years. This would be a huge mistake.
Finally armed rescue of foreign nationals is a very impressive show of determination and capability. Freezing of assets worldwide, stopping the export of arms, munitions and banknotes will create a dysfunctional state and weaken the Gaddafi grip. We have to leave it to the Libyan people to do the rest. It is their country. Iraq and Afghanistan have shown us that there is a line in the sand. We must not cross it.