If you want to backstab and still look fair, you should shout "Revolt!!!".
Not only that people won't call you a backstabber and team up against you, but they would even think of you as of someone heroic. Like Che Guevara (he did the same. killed people, and shouted "Revolt!", and everyone, whom he did not kill, thought that Che is heroic).
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So, easy as that. One phrase wins the game.

Good excuse for pga'ing too (well tested by myself).