Saddam Hussein rose to power by force. His regime ruled because it had the weapons to give it the power of law. In Somalia, the government is and was essentially a loose collection of warlords, maintaining territory, power, and (when food was plentiful) order by the strength of their weapons and their gangs of thugs. Similar descriptions can be made of virtually every dictator throughout history - that he ruled by the strength of his army; a living embodiment of the phrase "Might Makes Right."
Now, the United States has started down a similar path - not with its own people, but with the people of other nations. We say we are "liberating" the people from oppression, as if it is our duty and our honor, by virtue of the fact that we have the most powerful army in the world, to "liberate" everyone. But are we truly that morally superior to these other countries? When we point the finger at China or Sudan, Iran or Syria and decry their human rights violations, are we truly the ones without sin who shall cast the first stone?
It was often argued that the reason for invading Iraq was that they possessed weapons of mass destruction, and were an imminent danger to the United States. Indeed, most modern nations of the world agreed to the Geneva Convention, promising that we would not invade one another unless we were either defending outselves or were in imminent danger. Whether or not some or even most of the people of a given country want us to invade or not, or are unhappy with the government or not, we have never claimed that we are justified in invading a country for any reason other than actual danger to our own people. (Now, if Iraq turns out to not have had weapons of mass destruction, and thus was incapable of posing any threat to the United States at all, it may be argued that we violated some serious international laws.) Invading another country simply because we don't like its form of government, or because we sympathize with its people that they don't get the best end of the stick, seems to me to be arrogant, and approaches "Might Makes Right." Not ven the catechism supports that sort of military action.