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.
So many people seem to not be able to understand this.
Our diplomatic efforts with Sadam couldn't succeed, because he never believed we would attack.
Since we have proven that we are willing to go to war if necessisary we have much more credibility in our negotiations now.
Syria has definately started playing nicer recently. A lot of it is just talking nicer and putting on a show of not actively undermining our interests, but it's progress.