Qualifications for President and the 'Natural Born' Citizenship Eligibility Requirement [November 14, 2011] [open pdf - 570KB]
"The Constitution sets out three eligibility requirements to be President: one must be 35 years of age, a resident 'within the United States' for 14 years, and a 'natural born Citizen.' There is no Supreme Court case which has ruled specifically on the presidential eligibility requirements (although several cases have addressed the term 'natural born' citizen), and this clause has been the subject of several legal and historical treatises over the years, as well as more recent litigation. […] Although the eligibility of native born U.S. citizens has been settled law for more than a century, there have been legitimate legal issues raised concerning those born 'outside' of the country to U.S. citizens. From historical material and case law, it appears that the common understanding of the term 'natural born' in England and in the American colonies in the 1700s may have included both the strict common law meaning as born in the territory ('jus soli'), as well as the 'statutory' laws adopted in England since at least 1350, which included children born abroad to British fathers ('jus sanguinis', the law of descent). The weight of legal and historical authority indicates that the term 'natural born' citizen would mean a person who is entitled to U.S. citizenship 'by birth' or 'at birth,' either by being born 'in' the United States and under its jurisdiction, even those born to alien parents; by being born abroad to U.S. citizen-parents; or by being born in other situations meeting legal requirements for U.S. citizenship 'at birth.' Such term, however, would not include a person who was not a U.S. citizen by birth or at birth, and who was thus born an 'alien' required to go through the legal process of 'naturalization' to become a U.S. citizen."
CRS Report for Congress, R42097