Nukewar (1980)

The time is the late 20th century. You and a neighboring country have developed a nuclear capability. Your neighbor's sole objective is to utterly annihilate you. As the tension mounts while you are conducting espionage, building bombers,missiles,submarines and anti ballistic missiles either you or your neighbor launch a pre-emptive first strike.The nuclear destruction continues until either all weapons are expended or a truce is negotiated. Victory is determined by population remaining and world political opinion which is usually against the side that started the war. If both sides lose enough people neither will win.