At Informed Comment, Juan Cole shows us a map of the percentage of people holding passports by state and has this to say about it,
Lack of experience with the world seems to track pretty closely with strong opinions about how to deal with the rest of the world. It also tracks with socially reactionary views.
Or as Mark Twain said,
You never saw a bigoted, opinionated, stubborn, narrow-minded, self-conceited almighty man in your life but he had stuck in one place ever since he was born and thought God made the world and dyspepsia and bile for his especial comfort and satisfaction. – “The American Vandal Abroad,” c. 1868
Dr. Cole has a few other choice informed comments. Check them out.