President Obama has prove once again that he does not understand the principles of negotiation. This shows up in the trouble he is in because he announced his red line in the Syrian conflict. He announced to the world that if Syria used chemical weapons that would be crossing his red line, after which he would take military action against Syria.
When you make such an announcement to the world, anyone who wants you to attack Syria now knows what has to be done to get you to take action. Who would want you to take action against Syria? Some of the rebels in Syria would certainly want you to take action. Some people in your own government want you to take action. They also know that it must look like the Syrian government did it.
If you must have a red line, you should only tell where that red line is to the people who would not want you to take action.
Announcing red lines is akin to going into a negotiation to sell something at a particular offering price, but announcing up front what is your actual minimum acceptable price. Obama has already proven himself to be a past master of this technique.