I have to say that the idea of an arbitrary limit on terms seems like a bad hack to fix a dysfunctional democracy. It's at least as likely, if not more so, to eliminate a good leader and clear the way for one of several bad leaders to get in. In a working democracy, people would not put up with a bad leader for more than the remainder of a term, after they show their true colours. In a highly functional democracy, a visionary leader should be able to initiate multi-generation projects and see them through to completion.

Is this a scheme to prevent the members of a two party system from coalescing into a single party?

Yes, it's a safety valve to guard against dysfunctional democracies. It's a compromise, and yes you will limit the service of both good and bad leaders, but that doesn't make the compromise any less valid. Many people fear change, and don't like to admit they made a mistake, and base a lot of their vote on personality rather than achievement, and as a result of these factors people can keep voting for someone even if they do a poor or mediocre job.

I personally believe the best form of democracy would be something along the lines of a liquid democracy, coupled with a constitution that protected the rights of everyone (to ensure those with minority viewpoints would always be entitled to a base level of respect). If you're interested in finding out about liquid democracy, this video provides a good introduction:

https://m.youtube.com/watch?v=fg0_Vhldz-8

Why do you assume that there's at most one good leader?

The problem that I was referring to above, is that a good leader might be able to rule for 40 years, if there were no term limits. Leaders who are worthy of that privilege / burden are so rare though, that if you eliminate on just because of an arbitrary limit, then they will likely be replaced by some worse than them. Bad rulers are unlikely to win a third term in the first place, assuming that the electoral system is working.

Because I'm an incorrigible optimist? No but seriously, do you have any anecdotes regarding an election where a difficult choice had to be made between multiple good (from the perspective of a large majority) candidates? Because I don't (Canadian, in my 30s).

The parent comment by yxhuvud mentioned Kekkonen in Finland. He was the president for about 25 years in the '60s and '70s.

That concentration of power was so traumatic to the political system that, for the next 20 years, a long sequence of steps were taken to prevent it from happening again. Presidential terms were limited to a maximum of two, and the constitution was eventually rewritten in a direction that removed the presidential powers that Kekkonen used (and abused) to override parliament.

Perhaps you misunderstood my comment. I basically said that I thought having a maximum length of service was a good idea, but I didn't think two terms was the right target. Perhaps three terms would be a better target. The reason I think three terms is better is that you want the leader to have to face up to their own mistakes. It strikes me that with one or two terms there's still a tendency to blame your predecessors for the state of the country rather than accepting responsibility for the cock ups.

Developed countries almost all have some form of term limits:

https://en.m.wikipedia.org/wiki/List_of_political_term_limit...

In a lot of the cases listed there, the term limits mean that a new election must be held every X years, but not that the party/prime minister/president cannot be reelected. So it's not quite the same as in the US.

Err, no. If you browse around Europe (and elsewhere) you'll see a lot things along the lines of no more than two consecutive terms.

Depends on your definition of leader. For example, in Germany the President can only serve 2 terms, but the Chancellor has no such limit, and the Chancellor appears to have a much greater role in day-to-day politics. Many people in Europe are familiar with Angela Merkel. Same recognition for Joachim Gauck? Not so much. His role appears to be more of a figurehead.

https://en.m.wikipedia.org/wiki/Angela_Merkel

https://en.m.wikipedia.org/wiki/Joachim_Gauck

Mexico does (not sure what you count as developed countries :). I think most non-parliamentarian democracies do.