"To summarize: it is a well known fact, that those people who most want to rule people are, ipso facto, those least suited to do it. To summarize the summary: anyone who is capable of getting themselves made President should on no account be allowed to do the job. To summarize the summary of the summary: people are a problem.
"And so this is the situation we find: a succession of Galactic Presidents who so much enjoy the fun and palaver of being in power that they very rarely notice that they're not.
"And somewhere in the shadows behind them - who?
"Who can possibly rule if no one who wants to do it can be allowed to?"
Chapter 28 of The Restaurant at the End of the Universe. The Hitch Hiker's Guide to the Galaxy.