President Obama told CNN's Chris Cuomo that Wednesday's alleged chemical attack on Syrian civilians was "clearly a big event of grave concern" and agreed that the U.S. faces "an abbreviated timeline" in crafting a response.

Appearing on New Day, the president said that "core national interests" of the U.S. are at stake, and his administration is pushing the U.N. for "better action." But he refused to commit to any particular response, saying only that "we have to think through strategically what's going to be in our long term national interests." In other words: Maybe we will! Maybe we won't! (France and Turkey have both called for intervention, pending confirmation of the chemical attack.)

But at least the president acknowledged that there are major legal constraints on action—even if the Syrian government has crossed the "red line" of chemical weapons, which prompted an inflow of weapons from the U.S. in June:

"If the U.S. goes in and attacks another country without a U.N. mandate and without clear evidence that can be presented, then there are questions in terms of whether international law supports it," Obama told Cuomo.

"Do we have the coalition to make it work?" he asked. "You know, those are considerations that we have to take into account."

The costs of military action "have to take those into account as we try to work within an international framework to do everything we can to see Assad ousted," Obama concluded.