Ford explained, “On that world, the people are people. The leaders are lizards. The people hate the lizards and the lizards rule the people.”

“Odd,” said Arthur, “I thought you said it was a democracy.”

“I did,” said ford. “It is.”

“So,” said Arthur, hoping he wasn’t sounding ridiculously obtuse, “why don’t the people get rid of the lizards?”

“It honestly doesn’t occur to them,” said Ford. “They’ve all got the vote, so they all pretty much assume that the government they’ve voted in more or less approximates to the government they want.”

“You mean they actually vote for the lizards?”

“Oh yes,” said Ford with a shrug, “of course.”

“But,” said Arthur, going for the big one again, “why?”

“Because if they didn’t vote for a lizard,” said Ford, “the wrong lizard might get in.

The Hitchhiker’s Guide to the Universe