It depends on what you do with wars: whose "fault" is the death of roughly ten million Germans in World War II?
I think the place to draw the line is at setting whole cities on fire. Bombing railroads and districts with tank factories in them is not a war crime. Trying to set whole cities on fire is.
By that count Truman gets roughly 200,000 skeletons--say, one-fourth of a Suharto. Roosevelt gets half a Suharto. By my (rough) count Reagan gets perhaps a tenth of a Suharto, and Nixon and Johnson together make it up into the Suharto range.
Pinochet gets maybe a tenth of a Suharto. Ho Chi Minh is maybe a Suharto and a half.
Castro I don't know enough about, but I suspect he is in the tenth-Suharto range. Kim Il Sung is probably in the three Suharto range. Pol Pot is also in the three Suharto range--but he gets extra points for "enthusiasm" given Cambodia's small population base.
Lenin and Chiang Kai-Shek are in the roughly ten Suharo range.
The servants of the Showa Emperor make it up to the 10-20 Suharto range.
Mao, Stalin, and Hitler are in the 30-60 Suharto range.