They were added while applying for driver's licenses or identification cards.
As President Trump looked on during an unprecedented visit to the Supreme Court, a majority of justices appeared skeptical of his administration's bid to end birthright citizenship.
The bill, would require Americans to prove they are citizens when they register to vote, mostly through a valid U.S. passport or birth certificate.
A judge permanently blocked two provisions of the executive order that sought to impose proof-of-citizenship rules.
Fidel Rivera, a husband and father who has been in the U.S. for 30 years, is one of thousands of undocumented migrants who have self-deported due to the threat of arrest.
President Donald Trump's administration is asking the Supreme Court to uphold his birthright citizenship order declaring that children born to parents who are in the United States illegally or temporarily aren't American citizens.