Syria & Iraq. Numbers.
Syria:
According to various sources, including the United Nations, up to 13,00018,700 people have been killed, of which about half were civilians, but also including 5,8606,470 armed combatants from both sides and up to 1,400 opposition protesters. Many more have been injured, and tens of thousands of protesters have been imprisoned. According to the Syrian government, 9,71010,046 people, including 3,0903,360 members of the security forces, 2,7753,115 insurgents and up to 3,600 civilians, have been killed in fighting with what they characterize as "armed terrorist groups".
http://en.wikipedia.org/wiki/Syrian_uprising_%282011%E2%80%93present%29
Iraq:
In the invasion phase of the war (March 19-April 30), 9,200 Iraqi combatants were killed along with 7,299 civilians, primarily by U.S. air and ground forces.[138] Coalition forces reported the death in combat of 139 U.S. military personnel[139] and 33 UK military personnel.[140]
http://en.wikipedia.org/wiki/Iraq_War#Invasion
Bush was in all likelyhood worse than Assad. If we are going to go after war criminals let's start with the ones at home.