Washington: The Supreme Court seemed poised Wednesday to reject US President Donald Trump’s restrictions on birthright citizenship in a momentous case that was magnified by his unparalleled presence in the courtroom.

Conservative and liberal justices questioned whether Trump’s order declaring that children born to parents who are in the United States illegally or temporarily are not American citizens comports with either the Constitution or federal law.

Arguments lasted more than two hours in a crowded courtroom that included not only Trump, the first sitting president to attend arguments at the nation’s highest court, but also Attorney General Pam Bondi and Commerce Secretary Howard Lutnick, and in seats reserved for the justices’ guests, actor Robert De Niro.

The case frames another test of Trump’s assertions of executive power that defy long-standing precedent for a court with a conservative majority and a robust view of presidential power, which has largely ruled in the Republican president’s favour. In the notable exceptions when the court has not, Trump has responded with starkly personal criticisms of the justices. A definitive ruling is expected by early summer. Trump, the media-savvy president, spent just over an hour inside a courtroom that prohibits cameras and all electronic devices for arguments made by the Republican administration’s top Supreme Court lawyer, Solicitor General D John Sauer. The president departed shortly after lawyer Cecillia Wang began her presentation in defence of broad birthright citizenship.