We have drones and nukes and yet somehow still fighting persisted for a decade in Iraq and Afghanistan. Guerilla warfare is a very real thing.
As for nukes, What would be the point of the united states dropping a nuke on say, a rebellious Chicago? They'd be fucking themselves over. There are plenty of decent arguments one way or the other, but let's not be stupid.
What is something you used to believe, preferably something concrete with direct or implied predictions, that you now know was dead wrong. Was your belief rational given what you knew and could know back then, or was it irrational, and why?
Edit: I feel like some of these are getting a bit glib and political. Please try to explain what false assumptions or biases were underlying your beliefs - be introspective - this is LW after all.