The Supreme Court’s decision striking down President Donald Trump’s birthright citizenship executive order has forced Republicans to rethink how, or whether, they can still achieve one of the administration’s top immigration priorities.

The high court ruled Tuesday in Trump v. Barbara that the president could not use executive authority to deny citizenship to children born in the United States to parents who are in the country illegally or temporarily. While his executive order was invalidated by a 6-3 decision, only a 5-4 majority reached the constitutional question, holding that the 14th Amendment protects birthright citizenship in those circumstances.