I'm with Eomer on this one. Assuming the Assad regime used chemical weapons, we should respond with force in light of the President's insistence that the use of such weapons would cross a red line.
This raises a host of issues and I think it's important to keep them separate.
1) Did The Assad Regime Use Chemical Weapons?
There's obviously no need to respond to something the Assad regime didn't do. I've seen a lot of perfectly reasonable speculation that the rebels used chemical weapons themselves to draw a response from the U.S. So, I'd like to see some of the evidence that it was the Assad regime. I expect, even among those that would support a military response if the Assad regime used the weapons, that different people will require different amounts of evidence before they are convinced of who is responsible for using the weapons. I'm not sure how much would be needed to convince me.
2) Why Respond At All?
Appearances matter, especially on the world stage. China is watching, Russia is watching, Iran is watching. America shouldn't allow a country to do the one thing we said it couldn't without repercussions. Our name is our name.
3) Was It Smart To Draw The Red Line?
Eomer pointed out the chemical weapons red line is nothing new. Still, I think it was not in our interests for Obama to repeatedly make a point of it in speeches. Had he not, we'd have more options open to us now. That's good for future discussion, or to the judge the President, but has little to do with the current decision.
4) What Should The Response Be?
I'm not sure. I'm not a military guy. My inclination is it should be less than the Iraq invasion and more then sending a few cruise missiles to blow some shit up.
5) What About WWIII?
There are so many moving parts here, and so many uncertainties that I doubt whether anyone could accurately predict the consequences of acting and failing to act. Sure, you can trot out a parade of horribles caused by a military response, but it's just as easy to trot our a parade of horribles caused by appearing weak.