President Assad is a hard nut and is not likely to give up power easily. He has activated his links with Russia and found a friend in Vladamir Putin the Prime Minister. Putin feels the USA is a pain in the neck and also would like to restore parity with the USA like the erstwhile Soviet union. Accordingly he has sold 3 coastal batteries to Syria. As per last reports these batteries have been positioned on the Syrian coast against Naval invasion by NATO.
At the same time Assad has also activated his air defences against NATO aircraft. The aim is not to give the USA and NATO powers a walk over as given by Libya. The crucial role is of Russia, which has vowed not to let the NATO powers a free run on Syria. Vladamir Putin is also flexing his muscles and has also announced that the Russian Aircraft Carrier would be deployed of the coast of Syria as a deterrent to the NATO forces.
The fat is thus in the fire and the West is unlikely to get a free run and a easy victory as in Libya, where Qaddafi was effectively bottled up and was ultimately captured. at that time Qaddafi committed a cardinal blunder of not throwing his lot with Russia. He attempted to crush the rebellion on his own and also made overtures to the USA which were ignored.
Another factor is the Arab league which is towing the line of the West and has imposed sanctions on Syria. But the chance of an invasion by countries who make the Arab league is slim. Assad is now getting on against the demonstrators many of whom are being instigated by the West. The West is looking for an opening to crack on Syria, but it won't be easy. Assad is not Qaddafi and the factor of Russia cannot be ignored.