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.

The Supreme Court heard a blockbuster case on Thursday that impacts how challenging or easy it will be for President Trump’s executive orders to be enacted in the future, such as his order to end birthright citizenship for children born to undocumented immigrants.

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.