The debate today depends on whether, in 1868, foreigners were considered 'subject to the jurisdiction' of the United States. They weren’t.

Brad Jones, a professor of political science at the University of California Davis, told Newsweek. Birthright citizenship has been interpreted, repeatedly, as an integral part of the 14th Amendment. Trump isn't the first to weaponize birthright citizenship but he has been the most successful at bringing this issue to a boil.