Peter wrote "Yet it is estimated that between 45% and 50% of US citizens do not have passports and have never travelled outside their country. The majorty of those who do have passports are to be found on the east and west coasts. So the majority of those in the USA have never travelled abroad, know about other countries, their peoples, their societies and their problems only from their own media sources"
The USA is a large country, about the 3rd or 4th largest in the world thus there is little need to travel to other countries for tourism purposes. Even now land travel to Canada does not require a Passport. I have traveled to Mexico by land and did not need a Passport but that was 10+ years ago. You simply walked across a bridge from USA to Mexico to enter Tijuana, of course one would have some form of ID with them.My parents traveled to Canada and never held a Passport. But even so, about 50% of Americans do have a Passport, which, people wise, that is 170 million Passports in circulation, and increasing annually, which I believe to be the highest in the world.
Plus many people in USA have little incentive to travel abroad for whatever reason. As for knowledge of the countries, their peoples, their societies , etc, that all depends on their level of education, ethnic identity, and interests. etc. Kind of like the situation here in Thailand! 555