I would like to offer my theory of "just war" and it's very simple: you can't start a war. You can't initiate one. You can't be the first one to fire or drop bombs. And there are no exceptions.
Let's say you think the leadership of another country is doing terrible things to its citizens. You can't start a war over it. You can't invade and start destroying that country. Why? Because war means killing innocent people, and you can't rescue people by killing some of them. That's a contradiction in terms. So, you have to find another way.
There is plenty that can be done: withholding trade, withholding tourism, and withholding other exchanges that are normal part of modern life. You can document abuses and atrocities that you know of. You can get the UN to intervene, to demand to send watchers and inspectors to the country. International journalists can go there. You can ask religious leaders to condemn what is going on. The same goes for celebrities and sports heroes.
But, you can't start a war because that would surely kill more innocent people. And that you can't do, meaning: you have no right to do it.
What if the country is amassing weapons which you think they intend to use against you or your allies? Can you start a war then? Absolutely not. Look: since 1945, the world has lived with nuclear weapons- the worst weapons of all. If one had the right to attack a country for having nuclear weapons or trying to get them, we would have destroyed ourselves by now. And think about the hypocrisy if you are sitting on the largest arsenal of nuclear weapons, and if you are the only country that has ever used them, and you used them against civilians, as we did at Hiroshima and Nagasaki, and yet you assume you have the right to attack another nation because of their presumed intentions?
You can't attack another country for having weapons- not when the world is so stocked with weapons, as it is. The U.S., Russia, the UK, France, China, North Korea, India, Pakistan, and Israel have nuclear weapons (although Israel does not acknowledge it). Many more countries have chemical weapons, the largest stockpile being held by Russia, and the second largest by the U.S.
But, you can't attack a country for having weapons because you may be wrong about what they have and what their intentions are. And considering that the country most likely to attack has more weapons than anybody, it makes no sense. And if we are going to at all sane and civilized, we have to reject the insanity of starting a war, that is, actually using weapons, killing people with them, in response to a country just having them or seeking them.
It is a generally accepted principle of international law that nations have the right to possess arms to defend themselves and to determine their own needs. If we were to grant that one nation can attack another nation because it doesn't like its decisions about what arms to acquire and how many, it would amount to an unlimited right to start wars.
To actually attack another country because of the arms it has, or the arms you think it has? No. That cannot be considered legal or moral. And that's because: WARS KILL INNOCENT PEOPLE, and you have no right to kill them. Even though you are are trying to force another government to do something you want, the fact is: you are going to be killing innocent people. And, you have no right to kill even ONE innocent person.
What it really comes down to is that the greatest moral imperative is that WE don't kill people. Thou shalt not kill. It's just like the commandment says, and notice that there are no qualifiers after it.
If a person or a nation goes on a killing rampage, in other words, if they start warring, then there is the moral right to neutralize that person or nation. But, until they do, there is no right to start warring.
And, if you don't like the sound of that; if you think it sounds ominous, just remember what the alternative is. The alternative is what we did in Iraq, where we thought Saddam Hussein was accumulating certain weapons, so we went in and killed a million Iraqis. You have to remember that war is the worst thing in the world, and because it's the worst thing in the world, you don't start them. You don't use any rationalization to start them. That's none, nada, zip, zed, nunca.
You don't start a war to liberate people. Why? Because you are certain to kill some of them; that's why. There is no liberty in dying.
If you go to an Iraqi woman, and you ask her: "Would you rather have your dead husband alive but you have to put up with Saddam Hussein, or do you prefer to have him dead, but you get to have the government you have today?"
What do you think she is going to say? She's going to say that she'd put with Saddam Hussein for 1000 years if she could have her husband back.
Take a warmonger like Bill Kristol. He was in favor of removing Saddam Hussein from power, and he had to know that it was going to kill innocent Iraqis. So, how many Iraqis did you think you had the right to kill, Bill, in order to remove Saddam Hussein from power? Let's imagine for a moment that it could have been done with the killing of just one innocent person. No more. Just one. However, that one innocent person had to be your wife, Susan.
So, what would you rather have, Bill? A world in which Saddam Hussein is still in power, but Susan is alive and well and with you? Or a world in which Saddam Hussein and your wife Susan are both brutally killed? Take your pick.
Repeat: there is NO justified starting of ANY war.