Yes, I think that his proclamation about the Vietnam war being unwinnable by the US would affect politics because he was an influential news commentator and together with the strong and massive protests against the war within the US and actions like Muhammed Ali refusing to go and kill "Viet Cong" that these actions plus his words and the strong resistance of the Vietnamese National Liberation Front and mushrooming war costs together sapped the resolve of the military generals in the US Army in Vietnam.