I suspect you may be thinking of the "Trial of the Major War Criminals before the International Military Tribunal (IMT)" which was not a US only effort - it had judges from the UK, US, France and the Soviet Union, indeed the President of the Tribunal was Sir Geoffrey Lawrence, a UK judge.

After the International Military Tribunal there were US-led trials at Nuremberg but there were lots of different sets of trials held by the Allies in their parts of Germany and also by countries like Poland.

http://en.wikipedia.org/wiki/Nuremberg_Trials

http://en.wikipedia.org/wiki/Subsequent_Nuremberg_Trials

NB The IMT was in the US zone and did benefit a lot from the material support of the US.

Of course the IMT was a joint effort, it was unthinkable not to be; still, the initiative was mostly American (and from Soviets, to be honest, always sensitive to a bit of good propaganda). Churchill (with other "traditionalists") was much more inclined to old-school measures.

It turns out that the IMT was a fantastic idea, probably a bit too successful -- it made more difficult for nation states to (ab)use their military forces, at least until the end of the Cold War.

Interesting; the way non westerners thought about this was the Nuremberg trials as victors' justice. From that perspective, nothing America has been doing since then has been contradictory.

Indeed! Exactly to avoid that charge, Allied policymakers and judges went to great lengths to ground their accusations on solid and universalistic reasoning, that could be "reused" later. Without Nuremberg, international institutions like the UN would be even more powerless than they are now.

> Exactly to avoid that charge, Allied policymakers and judges went to great lengths to ground their accusations on solid and universalistic reasoning, that could be "reused" later.

I am not denying that happened. My point was that only the losing side was punished; you didn't see Roosevelt or Churchill taking the stand for the Dresden bombings? Neither did Hirohito get punished for Japan's part in the war. Realpolitik always prevailed. In fact, let us even take Iraq to this day, the UN thing that Powell did was a farce. However, did anyone get punished for that? I don't see Powell or Bush or Blair in a criminal court.

They still made sure nobody in their own countries could go after them for stepping over international law. That is an important factor, because it shows that even "imperial" power is now aware (and somewhat afraid) of the new legal framework and must take it into consideration.