As a recovering interventionist, let me emphasize the other point beyond legality: practicality. It's one thing to know that a dictator is evil and want to stop it, it is another whether we have political leaders capable of maintaining oversight and making the right decisions, the army trained for both fighting and building trust and institutions, and the public support that lasts throughout such a mission. Let me quote from something Billmon wrote prophetically on March 2, 2003 (two weeks before the war officially began), criticising Joshua Marshall (of Talking Points Memo):
Is there anything that suggests America is the right country to overhaul an ancient culture, riddled with religious and ethnic tensions, that got hung up on the conveyer belt between medievalism and modernity? Us? The guys who couldn't find most foreign countries on a map, and don't care? And are the American people really prepared to sacrifice the blood and treasure it would take to try?
And are the American people really prepared to sacrifice the blood and treasure it would take to try?
LOL. So you are against using interventions to help other interventionists seek the treatment they need? ;) Those who can make you believe absurdities can make you commit atrocities. -Voltaire
Having lived in and living close to the disintegration of Yugoslavia would alone have been enough for me to dismiss state sovereignity as an argument and wish for intervention. But then the medicine to the very same ill turned out to have been a different kind of poison... *Lunatic*, n. One whose delusions are out of fashion.