Mosul (US), bombing civilians in Yemen (US/Saudi Arabia with UK support).

The ultimate war crime according to the Nuremburg trial is a war of aggression. The attack on Iraq in 2003 over non-existent WMD should have seen George W. Bush, Richard Cheney and Colin Powell hung from the neck until dead like Hans Frank, Wilhelm Frick, Alfred Jodl, Ernst Kaltenbrunner, Wilhelm Keitel, Joachim von Ribbentrop, Alfred Rosenberg, Fritz Sauckel, Arthur Seyss-Inquart, and Julius Streicher.

President Trump and the current administration are putting themselves in a similar (il)legal position. Or do you not believe in equality before the law?

Strange to find you worried about democratically elected President Assad of Syria.

Professor Cole, the Syrians gave up their chemical weapons four years ago starting in September 2013. Syria is slowly winning the waragainst mainly foreign fighters funded by the US and Saudi Arabia. It's not even a civil war as the leaders and most of the troops of the rebels are not even Syrian nationals.

You write:

Al-Qaeda did not gas its own subjects.

Actually that's exactly what Al-Qaeda did in 2013. President Putin of Russia put his personal word on the line in the New York Times signing a wrtitten statement:

Under current international law, force is permitted only in self-defense or by the decision of the Security Council. Anything else is unacceptable under the United Nations Charter and would constitute an act of aggression.

No one doubts that poison gas was used in Syria. But there is every reason to believe it was used not by the Syrian Army, but by opposition forces,