President Donald Trump has sat in at the Supreme Court on birthright citizenship arguments in a first such appearance by a president but has left early. The Supreme Court is taking up one of the term’s most consequential cases, Trump’s order declaring that children born to parents who are in the United States illegally or temporarily are not American citizens. The justices on Wednesday are hearing the Republican president’s appeal of a lower-court ruling from New Hampshire that struck down the citizenship restrictions, which have not taken effect anywhere in the country. Trump spent just over an hour inside the courtroom, staying only for arguments by the government’s lawyer.