If only enforcement could let us realistically keep Trump from attending the G7 summit later this year in Kananaskis, Alberta. We have a law that says convicted felons aren't allowed to cross the border into Canada. The only people who want him to come are already his adoring fans."War crimes" are keeping Putin from traveling except to friendly nations.
As for "clean war", that's an oxymoron. War means someone dies and destruction happens, which automatically means it's dirty.
The closest anyone's come to inventing a "clean war" are those who wrote and produced an old Star Trek episode called "A Taste of Armageddon." Two planets at war for 500 years, waging war by computer, and anyone who's declared a casualty just calmly steps into a disintegration chamber and is zapped into nothingness.
This type of warfare is so "clean" and the people have been conditioned to accept it as so normal that they've had no incentive to make peace:
Is that the type of "clean war" people would prefer?