Sen. Jon Kyl wants to hold congressional hearings to see whether legal experts think Congress can prevent children of undocumented immigrants from becoming citizens merely because they're born in a U.S. emergency room. The rude phrase for this practice is "dropping anchor babies."

The debate is fraught with heavy in-group/out-group baggage. 93 House Republicans want to ban the practice, but there are significant constitutional questions. The 14th amendment holds that "all persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside."

There are no reliable statistics on the number of people who become citizens this way. Some Republicans want to repeal the language in the amendment that allows for this procedure, which was initially intended to ensure that Southern states did not deny citizenship to black babies.

Here is Sen. John McCain's extremely carefully-worded statement on the subject:

Congressional hearings are always warranted when member of Congress raise the issue of amending our Constitution. Our Founding Fathers intentionally made the process of amending our Constitution extremely difficult. I believe that the Constitution is a strong, complete and carefully crafted document that has successfully governed our nation for centuries and any proposal to amend the Constitution should receive extensive and thoughtful consideration. Immediate and full implementation of the McCain-Kyl 10-Point Border Security plan will assist in addressing concerns associated with this issue.