I found this article from the International Herald Tribune about the voting rights of American citizens who live abroad interesting. The article specifically focuses on Americans who have never lived inside this country. Which leads to an interesting question: Should these people be allowed to vote? Citizens by parentage alone, they have a tenuous link to America.
This problem (and the one described yesterday) could be easily solved by changing citizenship. Regardless of whether you or your parents were born here, anyone who had spent a substantial amount of their time (fifteen years or so) living in the United States would be allowed to take a "citizenship test," regardless of age or place of birth. I imagine this test would deal with simple concepts of American history, American political theory, and civics. If you passed, you became a citizen. If you did not, tough cookies.