The greatest success for any anti war movement is in extending wars.
Also, Leftist push the moral equivalent of War (because during a crisis you can do things you couldn't before you see)
The War of Poverty, the War on Obesity etc etc.
The Communists aren't Anti-War (Writ large either). Look at what Both World Wars were able to achieve for them.
Post WW-1 They got the biggest country on earth and post WW-2 they got even more.