“the song … is virtually a communist manifesto, even though I am not particularly a communist and I don’t belong to any movement. You see, ‘Imagine’ was exactly the same message, but sugar- coated. Now ‘Imagine’ is a big hit almost everywhere—anti-religious, anti-nationalistic, anti-conventional, anti-capitalistic song, but because it is sugar coated it is accepted. Now I understand what you have to do.
Put your political message across with a little honey.” - John Lennon

No, he was not a card-carrying Communist. But he was a communist.