I think my point was missed. Partly because I wasn't too clear about pointing out
Like GrudgeBringer above sayss to militarist, you either are "in the loop", or you are not. You know the people you trust to always to stick to their agreement, they know you. If you are in the loop, then you can count on the other players in there to cover your back. Wether you stick to agreements or not has no meaning, because those in the loop will kick out those not in.
It is the metagaming that can potentially kill the game, just as nearly happened to PBM Diplomacy in the 80's. Just as GrudgeBringer above says, he has a list of people he counts from game to game to cover his behind. If you are not on his list, there is nothing you can do; you will be on his target-list (because if you are not on the "trusted people who I count on to save my butt and who I thus don't attack what ever happens" -list, then you are automatically on that other list, as he has to attack *somebody* at some point
).