How would you go about stopping a dictator?

From both the right and the left there is a lot of talk about the end of democracy. Trump is a fascist, Biden is a commie, this guy is Hitler, that guy is Stalin.

But what if some president were to actually literally declare himself, in no uncertain terms, to be the dictator of the United States? In this scenario, we can't make it easy on you by assuming the military or government will stop him. Assume that government institutions bow down to this dictator. Only regular people such as yourself may decide to take action.
As a citizen, what do YOU do to stop him? What is the plan?

I ask this because I think we talk about the prospect of dictatorship without any idea of how we'd actually stop it. Militias exist. But I wonder whether they even have a tangible plan. Do they respond by attacking the local police station? Do they attack an army base?

Thinking about this, I think it becomes obvious that there's really no contingency plan. If such a scenario were to play out, there'd be a very chaotic response by the population, because nobody has ever really thought about this possibility seriously. And the less unified the response, the greater the chance the dictator holds on to power successfully.

How would you go about stopping a dictator?
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