Does Obama really need to choose whether he's a liberal or realist in Syria?

Dan Dresner thinks so.  In his view, a leak to the effect that Obama does not want the contemplated punitive strike to topple the Assad regime (in keeping with his slow-walked support of "moderate" rebel groups) clashes with intimations that Obama aims ultimately to push Assad out, as well as with his stated desire to uphold the international norm against chemical weapons.  Dresner's conclusion:

There are a lot of areas of foreign policy where different paradigms can offer the same policy recommendation, and there are a lot of foreign policy issue areas where presidents can just claim "pragmatism" and not worry about which international relations theory is guiding their actions.  I'm increasingly of the view, however, that Syria is one of those areas where Obama is gonna actually have to make a decision about what matters more -- his realist desire to not get too deeply involved, or his liberal desire to punish the violation of a norm.  If he doesn't decide, if he tries to half-ass his way through this muddle, I fear he'll arrive at a policy that would actually be worse than either a straightforward realist or a straight liberal approach. 

Busy work day ahead, so I will keep this short and maybe flesh out later, but I see a balancing act rather than a contradiction.
I think that what Drezner casts as Obama trying to "half-ass his way through a muddle" can just as easily be seen as navigating step by step through a minefield. Obama wants a negotiated solution that unseats Assad and incorporates elements of the regime in a government dominated by "moderate" forces within the opposition. He doesn't want the regime to collapse suddenly; he wants to tip the balance while strengthening elements in the opposition the US can support without strengthening jihadist groups in the opposition.. I see him trying to balance liberal aims and realism, rather than being driven to choose between the two. You may conclude that he's hurt the moderate elements of the opposition by going too slow with weapons and training, or you may think that trying to find elements in the opposition worth supporting, or worthy and capable of leading the opposition if they are supported, is trying to fill a sieve. But building and supporting a viable opposition is what the administration is trying to do.

One other quick thought: I noted with some amusement yesterday that the administration and supporters seem to have adopted as the party line Max Fisher's argument that the "red line" against chemical weapons is the world's, not Obama's. Of course they're also in up to the ears in the argument from credibility, that the U.S. has to do what it said it would do -- uphold that red line.  Really they're arguing that the red line is the world's, and Obama's, and Congress's, as Barbara Boxer pointed out.  No either-or need be implied.