Right now, it's simple: A birth certificate showing you were born in this country settles it. (Well, unless you're Barack Obama.) But once that rule is gone, all parents -- not just those who look or sound "foreign" -- would have to prove their citizenship.
Margaret Stock, an immigration attorney in Anchorage, Alaska, says that is not always as easy as it sounds. She often gets clients who assume they are citizens only to learn they are not, and she often gets clients who believe they are not citizens but actually are.
"It usually takes an expert immigration lawyer an hour to get through everything to find out," she told me. So intricately complex are the laws, she says, that "there are only a few hundred lawyers in the country who have the expertise to do it." For them, the repeal of birthright citizenship would be a full-employment act.
How complex are the laws? So complex that Obama might be a citizen even if he had been born in Kenya (which, let me emphasize, he was not). So complex that Winston Churchill, whose mother was American, could also have claimed citizenship.
Of course, you can always ask the kindly folks at the Department of Homeland Security to make the determination for you. But that option, says Stock, "is $600, it usually takes a year to do it, and they often make mistakes. Hundreds of people who are citizens have been told they're not, and hundreds of people who are not have been told they are."
Ultimately, she predicts, we would need a national citizen's registry, a national ID card and a host of federal employees to administer them. In the end, a lot more people would be subject to the unpredictable judgments of a distant bureaucracy.
Less comprehensible laws, administered by a larger and more powerful government? Consider it your birthright.