Sure; and there were massive civilian casualties in WWII. If WWII could be prevented at the cost of e.g. entirely obliterating Berlin in 1935, it would be "worth it", strictly as a matter of lives lost and saved. Would it prevent WWII? That's a valid subject for debate, and the debate would have gone differently in 1935 than now with the benefit of hindsight. Ditto for 1946.