Historical Rules · 29 September 2017
Rule 801.5c
Official source text from the 29 September 2017 Rules release
If an effect requires a choice and there’s no player who can make that choice within its controller’s range of influence, the closest appropriate player to its controller’s left makes that choice. Example: In an Emperor game in which all players have range of influence 1, an emperor casts Fact or Fiction, which reads, “Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.” Since no opponent is within the emperor’s range of influence, the nearest opponent to the emperor’s left separates the cards into piles.