Obama's indecision and political inclinations reinforced the status quo inside Syria -- terror, bloodshed and the prospect of endless war. If you're Assad and you are willing to employ any means to cling to power, Obama has effectively demonstrated that you can carry on while ignoring the rhetorical threats of outside intervention.
President Obama has reframed his position on Syria, adjusting the Red Line metaphor: It wasn't his Red Line, not his responsibility for drawing it. It was the Red Line drawn by the world, by the international community -- both legally by international treaty, and morally by universal revulsion against the use of poison gas by Assad. It was also America's Red Line, imposed by America's commitment to live up to such treaties. The reframing fit his previous rationale for the Red Line: to uphold international treaties on weapons of mass destruction, both gas and nuclear weapons. By this logic, the Red Line therefore applies not just to Assad's use of sarin, but potentially to Iran's development of nuclear weapons. The new version of the metaphorical policy has broad consequences.