Donald Trump became the first sitting president to attend Supreme Court oral arguments during a hearing on his executive order to end birthright citizenship.The case arrives at the high court following lower court rulings that blocked the administration from denying citizenship to children born in the US to undocumented parents.With an impact on 250,000 births annually, the legal battle focuses on the interpretation of the 14th Amendment and is expected to reach a final decision by early summer.Lawyers for the American Civil Liberties Union argue the order contradicts long-standing legal precedents and federal law while protesters gather outside the building.