A free Afghanistan, a free Iraq, Arafat's death, reforms around the Muslim/Arab world, rallies in Iran, uprising in Lebanon, and so on...The Syrian terrorist regime is very, very nervous and frightened.
That Assad thinks we may attack him is a sign that diplomacy is working.
The biggest mistake Saddam made was thinking what we'd never actually attack, so we had to do it to prove him wrong. If Assad believe we would attack, he will have to comply with internationals demands to ensure that we won't.