Woe to those who began this war if they were not in bitter earnest—Mary ChesnutMs. Chesnut's words were written over 150 years ago, but they deserve remembrance today. Especially today.
In less eloquent phrasing: do not take military action, unless you are certain that the consequences of that action unequivocally outweigh the consequence of inaction. In less delicate terms still, don't pull that damn trigger unless you're sure it's worth it.
And by worth it, I don't mean worth the cost of a few Tomahawk missiles and a photo op. I mean worth American blood. American lives. Don't give me this "no boots on the ground," bit. First, because it's bullshit. We can't know where this will lead. Second, because it's dangerous. Not only can no one predict where this will end once started, but the pretense of the "surgical strike" is leading America down a very, very sorry path; one in which we can execute our actions without cost or concern. We've already taken several steps down that path, and it's a direction at least as dark as the one we claim to be drawing a "red line" against now. You cannot rally the world against one moral outrage while wielding another.
If you're going to do it, then be straight with us. Don't sell this as some kind of terrorist threat. It's not. You know it. Application of the "terrorists might get us" meme to this discussion is at best distracting, and certainly disingenuous.
If we're going to do this, we're doing it because we believe use of chemical munitions is a tactic so horrible it can not be permitted at any time by anyone. Sell us on that if you can. Sell us on how this will save lives in the future—the immediate future, and the distant. But don't drag some hand waving about terrorists into this, and don't raise the ghastly, repugnant idea of war as punishment.
If we're to follow you, then be in bitter earnest. Be ready to put boots on the ground. Be ready to commit blood and fortune.
Or take your finger off that trigger.