The Supreme Court on Thursday seemed open to lifting a series of nationwide orders blocking President Donald Trump from enforcing his birthright citizenship policy, even as several of the justices wrestled with the practical implications of allowing the government to deny citizenship to people born in the US.

Federal courts have so far uniformly blocked President Donald Trump’s order seeking to end birthright citizenship for children born in the United States to someone in the country illegally.

In a case involving changes to birthright citizenship, the justices heard arguments on whether a single federal judge in a single district can block Trump administration policy across the country.