The U.S. Constitution uses but does not define the phrase "natural born Citizen", and various opinions have been offered over time regarding its precise meaning. The consensus of early 21st-century constitutional scholars, together with relevant case law, is that natural-born citizens include, subject to exceptions, those born in the United States. Many scholars have also concluded that those who meet the legal requirements for U.S. citizenship "at the moment of birth", regardless of place of birth, are also natural born citizens.[2][3] Every president to date was either a citizen at the adoption of the Constitution in 1789 or was born in the United States;