There's actually some data on this, and short answer is that immortal dictators would only last an average of 4 more years, because death isn't usually the bottleneck for dictator survival:
https://forum.effectivealtruism.org/posts/P9WGcRRa2cfAGeRvT/against-immortality#GPKWcB5xenEhRBtRk
The difference between leaders in dictatorships and in democracies isn't so much in the average time they rule, but in the variability in the time they rule. Yes, not ageing wouldn't help someone like Bachir Gemayel who was assassinated after two weeks in office, but it would probably have helped a leader like Stalin. So I care more about the variability of how much no-ageing would help dictators than the average. But still, I agree ageing isn't the main bottleneck on dictatorship.
In the past, dictators died, but monarchies sometimes survived for generations. The mortality of the kings did not necessarily bring liberty to their subjects.
Dynasties still have the effective term limit of the ruler’s lifespan. Term limits add dynamism to a system, with new men and women bringing new ideas. Death does not guarantee liberty, but it does change. Change preserves the possibility of liberty and not the thing itself. A monarchy is one of the least optimized examples, but forever leaders would be worse, tailoring an entire political system around a single person's nature. Term limits do not guarantee good governance, but they prevent consolidation of power and stagnation. But term limits are just a law and can be overturned as they have been in some countries.
I was slightly tempted to downvote on the grounds that I don't want to see posts like this on LW, but the author is new so instead I'll leave this comment.
What I dislike about this post is that it's making an extremely obvious and long discussed observation. There's nothing wrong with new people having this old insight—in fact, having insights others have already had can be confirmation that your thinking is going in a useful direction—but I'm not excited to read about an idea that people have thought of since before I was born (e.g. Asimov's Foundation series arguably includes exactly this idea of what happens when a leader lives forever, for a slightly unusual definition of "lives").
My guess is that others feel the same and helps explain this post's lukewarm response.
I'd be more excited to read a post that explored some new angle on the idea.
Perhaps the solution is simply the “term limit”, but only one check is too fragile. I wonder what other mechanisms may help balance the systems that govern our societies.
A standard thing for dictators to do is to disregard or nullify any merely legal threat to whatever they want to do, whether that is term limits, elections, the constitution, or anything else. That is what a dictator is.
The problem is even more acute if we replace "dictator" by "artificial superintelligence".
One extreme solution, which I think is good regardless of this issue, is using sortition with high alternance, like they did in ancient Athens. I recommend Terry Bouricius' book on sortition.
There are actually a number of ways that you might see a permanently stable totalitarian government arise, in addition to the simplest idea that maybe the leader never dies:
https://80000hours.org/problem-profiles/risks-of-stable-totalitarianism/
“dictators die… and so long as men die liberty will never perish…”
This is an abbreviated quote from Charlie Chaplin’s “The Great Dictator” which stuck with me ever since the clip was played for me in middle school. Political but prescient, these words describe a natural limiter on any man’s ambitions. A check and balance that has guaranteed the downfall of many a dark figure, from Genghis Khan to Stalin.
But, and here it is, technology advances.
Advances in medicine, genetics and nano technology may soon combine to make death no longer inevitable. By solving one problem we move up the chain to face new ones. So even though we still die today, we may, regardless, want to start thinking about what happens when dictators do not, in fact, die.
Men and women with unchecked ambition may evolve into what I call “Forever Leaders”. They would persist without the problem of succession, ever consolidating power in their hands past any inside challenge. We can each postulate a few such individuals today that would-so evolve if radical life extension were to be invented tomorrow.
Perhaps the solution is simply the “term limit”, but only one check is too fragile. I wonder what other mechanisms may help balance the systems that govern our societies. For that I hope to start a small discussion.