In 2006, US immigration officials refused Boris Johnson, now mayor of London, entry into the United States on his British passport, saying that because he was born in the United States of America, they required that he travel on a US Passport into the US or have proof that he was no longer an American.  This proof is probably the Certificate of Loss of Nationality (CLN). Johnson writes:

So I circumnavigated America. I flew via Madrid, managing to beat the rest of my family to Mexico by 45 minutes; and yet I still seethe. It’s not just the stupidity of the rule that gets me. It’s the arrogance. What other country insists that because you can be one of its nationals, then you must be one of its nationals? Imagine if we told all British-born Americans that they could not arrive in this country except by use of a British passport. I haven’t seen anything so insanely possessive since the negotiations on the Common Fisheries Policy, when the Irish used to claim that the cod stocks of the Atlantic were still Irish in their fishy souls, even though they had long since emigrated to Portuguese waters.

As far as I can interpret the psychology of the rule, which has only been applied since 9/11, it is part of America’s new them-and-us mentality, the Manichaean division of the world into Americans and non-Americans, obliterating any category in between. Listen, buddy, the Americans seem to be saying. You got a right to be American? Then you do us the courtesy of travelling on the world’s number one passport when you come here. What you got to be ashamed of, boy?

I can tell you this:  the American tourist industry and airlines will lose a lot of business if a lot of accidental Americans have to circumnavigate the US.  This is dumb, dumber, and dumbest.  I too seethe.