So when you're at, say 8/8 with another player (the competitor) and the kingmaker player is identified, target the kingmaker with the robber instead of the competitor.
So when you're at, say 8/8 with another player (the competitor) and the kingmaker player is identified, target the kingmaker with the robber instead of the competitor. The kingmaker has limited resources anyway, so take them off her so she has little or nothing to give away. You will have a better-than-even chance of winning (due to having the stolen cards and your competitor not having those cards) instead of advantage going to your competitor and even if you lose, you will have the satisfaction of frustrating the kingmaker.