The age of tyranny is never dead. People either get wise or dumb. Governments stay the same.
And governments have no conscience, only policy.
Governments have been the same since Machiavelli destroyed the morals inherent in politics in the 1532.
Governments aren't going to change and be your friend just because they promise you entitlements.
All of the examples you mentioned earlier were of totalitarian dictatorships - you live in a democracy, It's even a pretty decent democracy, as far as they go. You honestly believe that your military would support a dictator president? Your soldiers are sworn to protect the U.S. from threats, both foreign and domestic. To defend the Constitution.
Besides, Your tiny guns can't save you from scuds and napalm. If your government was totalitarian, had the army on their side and wanted to subdue the population, they could do so. VERY easily. Guns would make no difference. This isn't Syria. The U.S. have no one to answer to, and in such a paranoid and hypothetical situation wouldn't think twice about levelling whole towns or cities.
Guns do not protect you from your government, and far stricter gun laws would be a blessing to your deeply disturbed (in relation to crime) country.