I am afraid I have to disagree with the basic concept of the "good" nation.
Every nation proclaiming itself as "good" while on a war of religion actually turned out to be quite the opposite, especially once someone mentioned doing it in the name of that Being we usually refer to as a benevolent, wise and just God.
This goes through the whole history of mankind... the egyptians certainly considered them "good" while happily enslaving and sacrificing the lesser tribes.
The spaniards in America, claiming to bring the word of God to the heathens while slaughtering them for their gold and burning their books.
"Torquemada's Dream" comes to mind, too... burning those different and purging the land from them - all the while the "people" cheered loudly during hangings and burnings. Entertainment had been sparse, and there's nothing like a good mob cheering the headsman on to produce a little bit more blood.
Nazi-Germany, they certainly considered themselves saviours of mankind, and most of the people (those not belonging to any prosecuted minority and those without (unusual for that time) high ethical standards) cheered them on, content in the knowledge that no matter how cruel and dark their masters' ways, it wouldn't affect them for now.
And, to add a bit of controversy, America, in all its self-righteous glory bringing the "good" to Vietnam and the (unspecified for the sake of flames) East.
I am afraid that the Geneva Convention is something blissfully unnatural to Human Nature, and a lot of things had to happen to get that one true.
So much for me showing off historical and philosophical background...
Anyway, I disagree with PoWs being treated well and costing supplies, in a time where the "powers" didn't even treat their own subjects that well. I am all for fanatical, Last-man-standing, death to all heathens war. As long as it remains a game, of course.