Earlier quoted context omitted.
One metric would be body count. 20th century Marxists are somewhere between 60 and 148 million dead. Hard to top that.
One thing that puzzles me is those people who shudder at comparing Stalin's murderous spree with what Hitler's effects were. Is it the cognitive dissonance of not wanting to believe that we not only allied with a genocidal dictatorship but heavily supplied them with industrial output during the war? My family lived in the USSR and I can say for a fact - knowing it was the NKVD rather than Gestapo that might knock on…
Churchill deliberately courted the Russians and prevented attacks on them early on in WWII to make it easier for them to switch sides, a very successful tactic which won WWII at the cost of Russian lives.
I’m one of those people who see China as a bigger threat to western hegemony and instead of using Ukraine to give Russia a bloody nose we should have again fermented divisions between Russia and China. It would have been possible to admit Russia into NATO, I know it sounds ridiculous but Switzerland was formed out of a having the bully canton join the alliance of smaller cantons that was expressly formed to defend against it. It can be done and there was historical precedent. Not anymore, China and Russia are now so joined at the hip they might as well be considered a single entity. I think the west overestimated its strength, and even now with the posturing for WWIII with fancy and expensive weapons it appears that the West doesn’t understand that warfare has forever changed. I did hope the Houthi conflict would have woken people up to that reality but somehow we’re holding on to this notion that a WWIII is winnable.
I should note that I lament the cost of these conflicts to human lives on both sides and wish smarter populations governed by astute politicians would have found ways to successfully avoid war, perhaps at the cost of a multipolar world which we’re likely to get anyway. I much prefer the Chinese way of fighting with ‘high tech overproduction’ and wish we could ‘fight back’ with our own overproduction. We would all be far wealthier for it, especially since the alternative is massively destructive.