I have heard it said that we shouldn't be the world's police and that the reason for Sept 11th is because we are always meddling in other countries' business. Why don't we let other countries deal with their own problems?
I say we SHOULD be the world's police and here's a metaphor explaining why:
Let's say that you were a black belt in karate and an ex-military special forces member.
You carry a gun and you yourself are a lethal weapon. Now, you're walking down the street and
you see some gang member (he's wearing his colors or something) beating up an old
lady or a little kid, raping a girl, or some other horrific act against someone who is more or less helpless to stop it.
At what point should you intervene? You're not a cop, so it's not your job. But you are more than capable and it's the right thing to do. As a consequence though, this gang member, and perhaps his whole gang might hate your guts, threaten you, or even hunt you down to harm and possibly kill you, and maybe your family too.
With all of your years of training and acquired skills as a trained fighter, if you don't help that person you not only be neglecting your responsibility but you'll forever walk around with the self-knowledge that you didn't act, that you were afraid of the consequences, in short - you acted like a coward. So to me the question is not "should we be the world's police?", but WHEN should we be the world's police or WHEN should be intervene?
The answer to this of course is much less clear. I think there are three primary motivations that countries currently use for taking military actions against another country:
To defend ourselves (after Pearl Harbor, after 9/11, pre-emptive strikes against known enemies/threats, etc).
To perform some good deed in defending or liberating another country, people, culture, etc. A good cause of some sort.
Political or economic gain for the country or leader of a country.
In a perfect world, there would be an international organization that would determine when the second of the three would indeed be true and necessary according to some pre-defined standards, such as a ruthless dictator who is suppressing or eliminating his people through chemical or biological weapons, genocide, randomly cutting off people's genitals, requiring people to accept calls from telemarketers during dinner, etc. This organization would have no political motivation whatsoever. It would not benefit, profit, or achieve anything through its actions or decisions. Its purpose is simply to decide who needs help, and to what degree. However, because of political and economic preferences and influences, this ideal organization is largely impossible. I know that the United Nations could and should provide such a service, but I believe that it is unfortunately corrupt and generally self-serving.
Going back to the metaphor of helping the old lady, the good deed ceases to be good if the assistant becomes the assailant. In other words if, after helping her out, he decides to demand that she give him her money, or that she now owes him a life of slavery, his motives are now clearly far from pure and should not be recognized or rewarded by others. Or, if he only smacks the assailant and goes on his merry way, leaving the assailant to continue his assault, only slightly demoralized and now likely even more agitated, then he has instead done more harm than good. This is similar to Clinton launching cruise missiles at Iraq. Nothing was accomplished except annoyance and political publicity.
So to summarize, I am well aware that many of the United States international military efforts are self-serving in some way, be it for oil, to strengthen political allies, protect some sort of trade assets, or whatever. But I also believe that if military action could be taken to assist others for the betterment of humanity, then we are the most capable country to assist and as such, we should do so.
One last thing. We should not look at other countries as models for how and when to act, as usually no other country is willing to put their neck out and assist another in need. But just because there are plenty of passerby watching the crime occur, doesn't mean we are wrong to be the good Samaritan. Just because the cowards who refused to help also refuse to recognize our good deeds for what it is (lest they acknowledge their cowardice), doesn't make our acts any less heroic.