I don't think the "red line" has shifted much at all given the uncertainty over the use of chemical weapons in Syria. President Obama is right not to commit the U.S to any more than he already has, in light of the invasion of Iraq, which resulted in more than 100,000 Iraqi deaths.
Our record on bringing democracy to the Middle East isn't impressive. Let's allow the Syrians to sort it out for themselves.
Obama has recast his previously stated position on the use of chemical weapons in Syria as being a "game changer" into "rethinking the range of options that are available to us." This is unacceptable.