Last year, Barack Obama said that the use of chemical weapons by Bashar al-Assad's military would be crossing a "red line" that would force the international community to actHere's the quote to help refresh your memory:

"I want to make it absolutely clear to Assad and those under his command. The world is watching. The use of chemical weapons is and would be totally unacceptable. And if you make the tragic mistake of using these weapons, there will be consequences and you will be held accountable."

That was in December, but his position has not changed. Here's his Press Secretary Jay Carney, yesterday:

The President was clear when he said that if Assad and those under his command make the mistake of using chemical weapons or fail to meet their obligations to secure them, then there will be consequences and they will be held accountable. 

So did Syria use chemical weapons on its own people? Well, it seems somebody did. The Syrian state news agency said Tuesday that missile containing a chemical substance was fired. The rebels agreed. A news photographer said there were cases of "suffocation" among the victims and many witness reported smelling chlorine (though that isn't a definitive marker.) An Israeli cabinet minister is saying its "apparently clear." Even the conspiracy theorist who think the attack was a trumped excuse to escalate the war aren't doubting that weapons are there. They may all disagree on who fired the missile, but no one is denying that something bad happened in Aleppo.

The Israeli official quoted by the Associated Press also said it doesn't matter who is to blame, and he's right. The President would presumably agree that it would be just as unacceptable for the rebels to use a chemical weapon as it would be for Assad. And given all the evidence, it's almost impossible to argue that someone didn't cross a line in Syria this week.

So what are we going to do about it?

Carney took the cautious approach, saying they were "looking carefully" at the allegations. That's fine—look carefully. (The U.S. ambassador says there's no evidence yet, but we'd eyewitness accounts must count for something, even if it isn't proof.) But if the verdict comes back "yes," then what? Will U.S. troops invade, as Lindsey Graham has asked? Bomb the country, as Representative Mike Rogers suggests? Give the rebels all the guns they need, as France and Britain are close to doing anyway? The world agrees that the weapons are unacceptable, but few people want to talk about what the "consequences" are actually supposed to be for using them.

The president is in Israel right now, and perhaps he'll come back with a plan. Even if you only care about protecting Israel from loose weapons—and some people do care more about that than protecting Syria—promises have been made to Bashar al-Assad. Now the world is watching us, to  see if we'll back them up.