A federal judge is set to hear arguments over temporarily pausing President Donald Trump’s executive order seeking to end birthright citizenship for anyone born in the U.S. to someone in the country illegally.

A federal judge Thursday blocked President Donald Trump’s executive order outlawing birthright citizenship —the policy automatically giving citizenship to anyone born in the U.S.—and declared it “blatantly unconstitutional,” as legal experts widely believe the president does not have the power to change the policy on his own.