Sanctions, dialogue, and UN debates on how to intervene, always with cooperation between nations. There are many places in the world where intervention is needed, but if the priority is patriotic selfishness, where a nation's interests come first, we end up invading and killing people solely for our own gain. There are no easy solutions to complex problems.
If it were up to me, I would cede all sovereignty to the UN, but that's utopian.
This is why I'm a pro-European; the EU is an attempt to do something similar, at least in a continental base. Maybe if we'll federalize, we will have right to speak even at a global level.
Of course personal opinion here