What is just? no matter what you say, war is Just for one side, and un-just for the other.
An army cant fight if it doesnt believe what its fighting for is just. Trust me, im probably one of the very few people on this board who has had the misfortune of having to fight, and when your laying on the ground with someone spraying automatic rounds over your head, you dont care whether you should be there on not.
To decide wether a war is just or not, you have to look more deeply, you can argue for any war human-kind has ever had, was the alliance wrong for going into Iraq? well some say they were, for whatever reason, some say they are not? what difference does it make to the people of Iraq? none, it just means someone else is responsible for the countless deaths these people have to suffer. Vietnam, another prime example, should America of got involved? What give The US and UK governments the right to interfere in other nations doings, why are we so mighty? You can sit here and argue wether war is just or not, as long as you can sit here argue wether a glass is half-full or half-empty.