"Survival of the strongest" will always be apparent in society, which is one of the exact reasons communism would never be effective. There is always someone of a stronger disposition, whether that be physically, politically, or mentally, they will always be considered higher in the "food chain" of humanity.
Mental power seems to be more effective nowadays. You can be the strongest man in the world but if you're not intelligent enough, you'll end up working as a landscaper or carpenter. In the United States we have a government controlling us, not an army