Originally Posted by polonius

In fact, passports themselves were supposed to be eliminated. Even more properly speaking, they were eliminated -- twice. The need for passports was dropped by global convention in 1865. They were reïnstated as a temporary measure during WWI, and dropped again after the War under an agreement sponsored by the League of Nations. Again they were temporarily reïnstated during WWII. After the War, the newly formed United Nations agreed to again eliminate the need for passports, but the United States asked that although it supported the measure, it wanted to "temporarily" keep the need for passports in place. Most places are now in the process of removing passport requirements, except for the United States.