Cuba, Chile, Argentina. They all had democracies, and then collapsed into dictatorships. I'm sure someone more knowledgeable could also name some African or Middle Eastern countries.

I'm tentatively adding Turkey to that list.

As some others have pointed out, there is a lot of evidence that hear democracies were overthrown because of western influence.

Does that even matter? Democracy does not make you inmune to the rest of the world. Democracy is not only an idea and if you want to claim its robustness you have to make sure it is able to cope, in practice, with internal and external opposition, just like all other forms of government. I'm just pointing out that in many cases it has not.

Oh I totally agree, it almost seems that democracy works best when wealth and resources are abundant. This abundance is often at the cost of other nations, in which democracy probably won't last because of the external pressure.

iran

Iran got that because the CIA did it forcibly.

true, and true for Chile also (and probably more)

Can somebody unflag the Cuba comment? The US puppet dictators are hard to defend.

Germany as well.

The other countries people have stated make sense, I wasn't aware of a serious issue with Germany? Unless you're referring to Hitler?

As another example for "western democracy is not assured to work in the long run, many countries after adopting it have gone back to monarchies or dictatorships". So yeah, Weimar Republic.

When did Cuba have a functional democracy?