Easiest dunk is to show that the West REFUSES to let communism “fail” by itself. If socialism represented a bumbling oaf of a society, it would inevitably stumble and collapse of its own accord. No need for attacking Grenada, Vietnam, Laos with open warfare. No need to assassinate Allende or the many socialist politicians that were killed. No need to send armed forces to stop the Russian Revolution. If socialism was purely set up to fail, we wouldn’t see the PRC rising to become a major world power, etc. I could go on, but basically if it will fail, let it. Obviously the west doesn’t let it because it’s a shitty argument from the start, I GUARANTEE you that nobody (high ranking at least) in the US gov genuinely believes this. Maybe a few dumbass senators or Reps but Foreign Policy advisers, CIA/FBI, they understand that socialism is not going down on its own