GOP presidential candidates are falling over themselves to get on record with tough immigration plans. A string of them — Rand Paul, Chris Christie, Lindsey Graham, Scott Walker, Bobby Jindal and Rick Santorum — have spoken out in some form against birthright citizenship. That’s the idea that being born on U.S. soil, regardless of your parents’ legal status, automatically makes you a U.S. citizen.

Ben Carson went even further, saying he wants to secure the border — where he claims there are caves in which immigrants can hide — by using drones.

“You look at some of these caves and things out there, one drone strike, boom, and they’re gone,” Carson said.

When it comes to the issue of birthright citizenship, while some conservatives disagree, a lot of legal scholars believe it is settled law, enshrined in the 14th Amendment of the U.S. Constitution, and that it therefore would be fantastically difficult to overturn.