One of the reasons that humans play games and sports is that the final outcome is perfectly defined. The winner wins and the loser loses--or, in non-combative sports, a number is achieved that is reassuring in its absence of ambiguity.
Using chess as metaphor for political negotiation is dangerous and misleading. In chess, there is no information asymmetry, whereas in politics information is fluid, unreliable, and carefully guarded.
Chess has an endgame, and the only endgame in politics is nuclear annihilation.