President Obama should be asking the same question in Iraq and Syria. What course of action will be best, in the short and the long term, for the Iraqi and Syrian people? What course of action will be most likely to stop the violence and misery they experience on a daily basis? What course of action will give them the best chance of peace, prosperity and a decent government?

The answer to those questions may well involve the use of force on a limited but immediate basis, in both countries. Enough force to remind all parties that we can, from the air, see and retaliate against not only Al Qaeda members, whom our drones track for months, but also any individuals guilty of mass atrocities and crimes against humanity. Enough force to compel governments and rebels alike to the negotiating table. And enough force to create a breathing space in which decent leaders can begin to consolidate power.

On the legal side, we should act in both countries because we face a threat to global peace and security, precisely the situation the United Nations Security Council was established to address. If nations like Russia and China block action for their own narrow interests, we should act multilaterally, as we did in Kosovo, and then seek the Council’s approval after the fact.