i have a crazy question after ww2 the alies brought war crime charges on many german soldiers and head honchos.isnt war a crime? and war is anything goes to win??

Actually? It is but the spoils go to the victors. We really had no choice but to defend ourselves against Fascism.

Not all wars are crimes.

Two quotes from the internet  (links left out on purpose).

"A war of aggression was declared a war crime at Nuremberg."

"....................if another nation invades your country with violence, it seems right to defend your land and institutions, your people, by means of power as well. You can't expect to dialogue at a table when someone is shooting and throwing bombs.

The same think (sic) would apply if we know human rights are being absurdly disrespected by some other nation. Even if it is in its domestic arena, it would be justifiable if a country - again, after exhausting all pacific possibilities and warnings and dialogues - invades another that is, let's say, lining up kids and murdering them, or putting people in gas chambers and deliberately and summarily executing them.

This is something that, at level of humanity we have reached nowadays, no cultural relativism, no religion, no national traditions may justify. Those are values the international community have elected as universal. It would then be ok for another country to invade, using violence (because it would be noneffective otherwise) to cease this situation."

Invading a country is a crime. Defending your country or helping a country defend itself is not. As for war crimes, there are rules to war, and more specifically to how prisoners are treated. The Geneva Convention adresses this.

WWI was called "The war to end all wars". Humanity was so disgusted and horrified at what happened during that war "everyone" swore there would never be another war.  We all know how that turned out.