If You Can't Beat Them Join Them

( since we cannot defeat them, let's work together with them ... )

"If you can't beat them, join them" (proverb) says that if you cannot win against stronger opponents, then it is better to not fight against them; join together with them on the same team. Example: "When did you change teams?" Reply: "Hey: If you can't beat them, join them."

To make this saying more casual people might say, "If you can't beat 'em, join 'em" (replacing the word "them" with the sound "'em").