play both sides against the middle

play both sides against the middle

To manipulate two opposing sides of an argument, conflict, competition, etc., against one another for one's own benefit or advantage. My father and my uncle are engaged in a bitter business rivalry. If I can play both sides against the middle, I might be able to secure some sizeable investments for my own company. Janet really dislikes Mary and wants to date her boyfriend, Mike, so she's been playing both sides against the middle to get them to break up.
See also: both, middle, play, side