There is a popular science fiction concept, that of alternate dimensions that contain versions of us that made different decisions, or lived in worlds with alternate histories, and so their lives have been dramatically different than ours. This concept is true -- there are infinite such dimensions out there, with infinite versions of ourselves living out infinite variations of our lives.
What we don't know is that in one of those dimensions they have conceived of a way to cross into others. As a result, interlopers from those dimensions regularly exit their own, looking for preferable lives. When they discover a version of themselves who is enjoying a better life, they murder that version and take their life. This has happened several times in our world, unnoticed. Several of our current political leaders are unscrupulous doppelgangers who have stolen a life in this one, and are using that life to amass wealth and power, for themselves and their friends.