Ever since WW2 ended, america has not known how to fight a war. All they know how to do is arragne a bombing campaign. They have no idea how to make intelligent military decicions.
The war in iraq, for example:
The British troops advanced slowly and carefully across iraq in order to make sure they targeted the enemy and minimised civilian casualties.
The americans, however, just advanced as fast as possible (wanting to reach baghdad quickly), and fired at anything that got in their way, disregarding any civilian casualties.
The US army has nowhere near the discipline and training as the British army does.
/\the US regular army just recruits whoever it can find to enlist.
The UK army tends to be rather more selective in who it will take to be a soldier. The officer training is second to none, and the UK army has one of the most disciplined armies in the world.
being a good person is not the same as being an effective soldier.
In fact, most war crimes in iraq were caused by the lack of discipline. A well-trained soldier would not have let their emotions to cause them to do anything illegal. They should be professional about the job that they do.
"They should be professional about the job that they do."
Anyone in the army etc is professional about their job. How professional do you have to be to kill someone with a gun or a bomb? The term you are looking for is ethical, I believe. Or "moral". Even then, it's stretching it.
if soldiers let their ethics or their opinions of "right and wrong" , then they could end up killing loads of people, believing that they were doing the right thing.
What they should do is to obay orders and follow the codes of war (geneva convention), regardless of how emotional they may feel.