Unlike in Civ 2, cease-fires don't expire after 15 turns in the real world.
If someone puts a gun to your head and makes you sign over all your possessions to that person, it's not legally binding, after all. Or, if you kill someone, and the police coerce testimony out of you, the testimony is inadmissible, right?
Point being, you can't use your position of strength to make others bend to your will in civil society, so why should you be able to do it in international relations?
Comment