Pedzisa mutsara unotevera: Muna 1940, Marcantonio akabatsira kuumba American Peace Mobilization (APM), boka raiva nechinangwa chokudzivisa United States kupinda muHondo Yenyika II (nokudaro raiva nechinangwa chakafanana nechokurudyi America First Committee). Pamberi peMolotov-Ribbentrop Chibvumirano (chibvumirano cheNazi-Soviet chisina kurwisa) chakasainwa muMoscow musi wa23 Nyamavhuvhu 1939, sangano raitungamirira APM, American League for Peace and Democracy raitungamirirwa neComintern, rakanga riri rinopesana neNazi. Marcantonio akashanda semutevedzeri wasachigaro weAPM. Iye akaoneka mu newsreel muna 1940 achishora 'hondo yeumambo', mutsetse wakatorwa naJoseph Stalin nevatsigiri vake muSoviet Union kusvikira pakupinda kweSoviet Union neNazi Germany. Chibvumirano chacho chakapfuurira kusvikira vaGermany vachiputsa kupfurikidza nokupinda muSoviet Union pana 22 June 1941. Muna 1942 Marcantonio akashanda kuti awedzere kuzvipira kwechiuto cheU.S.
rutivi rwechipiri muEurope mukurwisana nokuwedzera kweNazi. USSR yakaraira vaKomonisiti munyika yose kusimudzira pfungwa yokuibetsera kukurira Nazism. Marcantonio akanga ariwo Mutevedzeri weMutungamiri weInternational Workers Order, sangano rehama rinobatsira risingazivikanwi neCommunist Party.