"Give us a leftwing dictator, and soon enough every rightwing wacko would be up in the hills with his rifle collection and enough ammo to sink the Titanic. (Not that the Titanic needed any help sinking, but you get the idea.) If things got worse, it wouldn't take long before the wackos were joined by their center-right comrades. The only difference between them would be the price of their guns.
Given a rightwing dictator, the results would be much the same, only more urbanized. Instead of ragtag bands of wanna-be soldiers hitting government convoys on isolated stretches of interstate highways, it would be our cities that would become ungovernable. And don't even try to tell yourself that liberals are too limp-wristed to put up a fight. Set your Way Back Machine to 1968 and think again."I would argue that left or rightwing tyrant would get all the people in the middle pissed. And I think it would be a BIG middle. Question would become who'd actually be willing to take up arms, and who'd keep talking until it was over for them? Socialist/communists have shown a great willingness to slaughter and imprison "for the good of all/for the revolution!"; far right types the same "for the good of all/for the leader!" So would the people in the middle be ready/willing to stomp on both extremes?
Seems like both extremes want control over everything. Difference seems to be the left wants everything including your thought processes controlled, their opposites often don't care what you think as long as you don't actually oppose them, and don't actually hate the idea of private property. Simplified, yes, but seems to cover much of it.