All but two countries in the Americas grant automatic birthright citizenship to people born within their borders, but that isn't the norm everywhere.

The U.S. Supreme Court will hear arguments on Thursday on President Donald Trump's bid to broadly enforce his executive order ending birthright citizenship, a principle that has been recognized in the United States for more than 150 years.

THE FACTS: This is not true. About 30 countries, including the U.S., offer unconditional birthright citizenship, according to the CIA World Factbook and the Library of Congress. Birthright citizenship was enshrined in the Constitution after the Civil War to ensure that formerly enslaved people would be citizens.