I don't believe in it, but my understanding is that many people do.

I'm not sure, but sometimes people do it to themselves; take Robert Mugabe for example. He has effectively trapped himself, as the President at the head of a failing government.

Possibly only clinging to power, as a lifeboat, the only thing that's keeping him alive. Fearing that if he steps down, he will not live long enough to enjoy his retirement.

The threat, coming not from his opponents, who want him alive, to stand trial, but his friends and accolites who don't want him testifying against them.