One of the proposals listed in Donald Trump’s immigration policy outline includes ending birthright citizenship for children of illegal immigrants, and presumably children of birth tourists who game the system in order to add a U.S. passport holder to their families. We estimate there are up to 400,000 children born to illegal immigrants every year and perhaps as many as 36,000 birth tourists annually.

Americans overwhelmingly support a more narrow application of the 14th Amendment’s Citizenship Clause than the one currently being employed. It’s not clear that Congress intended such a broad application of the Citizenship Clause or that a constitutional amendment is necessary to change how births to temporary aliens are handled. For an analysis of the issue, see my report, “Birthright Citizenship in the United States: A Global Comparison.”

There are two ways a president could attempt to narrow the scope of the Citizenship Clause: get Congress to write legislation or take executive action.