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I recently came across the article Harry Potter and the Half-Crazed Bureaucracy, an interesting analysis of Rowling's dark portrayal of government in the Harry Potter series. One of the first claims it makes is that the Potterverse government has no elections and no democracy.
Thinking about it, I don't recall any mention of elections in the series. Over a seven-year period in the Muggle UK, there should have been at least one general election, but the only changes of leader during this period in the magical UK are when a weak and discredited Minister resigns and when a psycho murderer takes over the government and kills the incumbent Minister.
How does a magical government take power? Are there elections which we just don't see (perhaps because the main characters are too young to vote)? Is the Ministry of Magic associated with a Muggle government like other ministries? Are there different political parties in the magical world?
Canon evidence only, please. I'll reluctantly accept evidence from the films, but no fanfic or unsourced Wikia claims.