Americans are naturally reluctant to build empires but our leaders have taken us into one war after another in the name of democracy over this century. The wars always seems justified until you look at our allies like Stalin, Saddam, and Osama Bin Laden and realize we are just sowing the seeds for the next crisis.
Pardon me, but this is bull$hit.
The war against Hitler and the Japanese was justified. Period.
If you don't believe that, imagine the world as it would have been had he been able to fight a war on the Eastern Front without worry about a Second Front. Then imagine his possession of the atomic bomb.
Your points about Saddam are well taken, but fail to recall our need to stop the ambitions of the ayatollahs in Tehran. That was our sole reason for our support of Saddam's war. We did not support the initial invasion, but once the fool went in, we could not afford to let him lose and allow Iranian Pasdaran and regular infantry to sieze Iraq's oil wealth. This is practical, pragmatic politics. I'm sorry it doesn't fit in with what you believe, but as Bismarck maintained, politics is the art of the possible. Deal with it.
As to bin Laden, you're merely parroting the canard that we created bin Laden. We did not. Bin Laden was his own man, motivated by his own inner demons and fanatical beliefs. People never give the sumbitch the credit that was his due for forming his own outfit. Weapons supplied by us did find their way to him, and he did get direct support from Pakistan's ISI, who had their own fish to fry. Most of our support went to the Mujahideen under Ahmad Shah Massoud. They successfully defended the Panshjir Valley against continues Russian armored and airmobile assault. Massoud was the best commander of the Afghan war. We put our money behind the right guy. The ISI backed Omar and bin Laden because they thought that they could control the "Afghan Arabs". That isn't the first stupid thing the Pakistanis have done.
As to North Korea, it is in the process of falling apart from within. We have no geopolitical reason to start a war there. Iraq has oil. Mate oil wealth with the capacity to create relatively primitive nuclear weapons. I shouldn't have to do the math for you.
Finally, as to international law. International law is upheld by the country with the largest navy. Other than that, international law is an artificial construct of agreements between states. Suppose you are invaded. Suppose you scream "international law". Will your invader withdraw? No, he will continue to kick your ass, rape your cows, and rustle your women. Unless, of course, you can convince a Great Power to drop by and apply a little "international law" to the situation at hand.
Be Seeing You,
Chris