Did Assad call the president's bluff in Syria?

http://www.washingtonpost.com/blogs/right-turn/wp/2013/04/28/obama-erases-his-red-line/
The president sounded hard core on the issue of the Assad family’s use of chemical weapons against the anti-Assad rebels. It appears that they called his bluff. It also appears that he is backing off his bluster.

Was this indeed a classic case of “calling the bluff”?

Is Iran and Russia, Assad’s buddies in the ME pretty interested in the response?