Birthright citizenship is based on the 14th Amendment, which most legal scholars interpret to include all children born on U.S. soil.
But shortly after returning to office last year, President Donald Trump issued an executive order limiting birthright citizenship to children born in the United States to U.S. citizens or lawful permanent residents, not illegal immigrants or temporary visitors
Federal courts have blocked enforcement of the order on constitutional grounds, but Ira Mehlman, media director for the Federation for American Immigration Reform, agrees with the president's contention that an important clause in the 14th Amendment has been ignored.
"The Citizenship Clause says, 'All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States,'" he quotes. "The Constitution does not go in for rhetorical flourishes, and 'subject to the jurisdiction thereof' is in that clause for a reason."
Mehlman says it disqualifies illegal aliens.
"'Subject to the jurisdiction of the United States' doesn't simply mean being here and abiding by the same laws as everybody else," he asserts. "There is a deeper meaning to it, and this is something that the Supreme Court is going to look at very, very closely."
Some analysts say the Court may avoid a broad constitutional ruling on birthright citizenship, instead focusing on whether the executive order can be implemented while litigation continues.
Others see the invitation to address 14th Amendment interpretation as a future confrontation that could happen on merits once the procedural issues are resolved, but most mainstream legal analysts do not think Trump's interpretation has strong legal grounds.
Mehlman hopes the Court's conservate majority realizes that the consent of the nation, not merely the will of lawbreakers or visitors, must play a role in who becomes a citizen of this country.
The Supreme Court usually saves the biggest cases for the end of the session, so a decision in this case is not expected until June.
