Vidor began filming in July 1939, just weeks before war was declared in Europe and the isolationist or interventionist policies were widely debated. The film influenced tropes that appeared in subsequent war films, depicting small military units operating behind enemy lines and relying on harsh tactics to destroy enemy combatants. The relevance of "Northwest Passage"’s sanguinary adventurer to contemporary Americans confronted with a looming world war is never made explicit but raises moral questions on "military virtue" and how a modern war might be conducted. Though Vidor was "anti-fascist" his political predilections are left unstated in "Northwest Passage".