If you tell people your plan, they can begin defeating your plan. So, maybe, Mr President, you need to learn when to say less, and when not to say more. Like the "line in the sand" think he trapped himself with, he has committed himself and his nation to taking down Assad in favor of the opposition.
Do you think issuing an unequivocal public warning to someone whom you suspect is about to use chemical weapons is a bad thing? I think any president (Democrat or Republican) worth his salt would have done the same. If we (the international community) do not make a stand on this, one of the worst breaches of international law in recent history, we will surely be setting a chilling precedent for all wars to come.
I cannot put it better than Lord Ashdown did:
"Seventy-seven years ago the League of Nations, the UN’s predecessor, faced a crisis.
Italy, flagrantly breaching international law, invaded Abyssinia. The League failed to act because Germany and Japan effectively vetoed it. From that moment, the League ceased to exist as an effective institution and was put out of its misery in 1939. Prime Minister Baldwin told the Commons, the League “failed ultimately because of the reluctance of… nations… to proceed to… military sanctions”.
What has happened in Damascus is a challenge to our humanity. It is also a challenge to our system of international law.
If the international community will not now find the means to make it clear that we will not tolerate the use of weapons of mass destruction, like poison gas, for the mass murder of innocent citizens, then the fragile structures of international law that we have painfully erected these last twenty years will be undermined, and the threat of the future use of weapons of mass destruction will be widened."