The Constitution gives 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,” a term not defined in the Constitution.May 9, 2013” — Article II, Section 1, Clause 5
No Person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution, shall be eligible to the Office of President; neither shall any Person be eligible to that Office who shall not have attained to the Age of thirty five Years, and been fourteen Years a Resident within the United States.
Undivided loyalty to the United States was a prime concern. During the Constitutional Convention, John Jay wrote to George Washington, urging “a strong check to the admission of Foreigners into the administration of our national Government; and to declare expressly that the Commander in Chief of the American army shall not be given to nor devolve on, any but a natural born Citizen.” Justice Story later noted that the natural-born–citizenship requirement “cuts off all chances for ambitious foreigners, who might otherwise be intriguing for the office.”
So, goodbye Cruz and Rubio!