According to Article II of the Constitution, a person "shall be eligible to the Office of President" if they are 35 years old, a resident of the United States for 14 years, and a "natural born" citizen. The first two criteria are straightforward. However, because the Constitution does not define "natural born," and because the Supreme Court has not interpreted the phrase, there is a constitutional debate on its true meaning.
"That Would Be Enough"
The Founding Fathers did not record their thoughts on the issue of "natural born" citizens. In fact, at least one of the Founders, Alexander Hamilton, was born outside the US. In the absence of either a definition or commentary during the Constitutional Convention, the Supreme Court has said terms "must be read in light of British common law." Legal scholars have examined British traditions and laws in practice at the time of the writing of the Constitution to shed further light on the matter. Under common law, persons born on English soil, even of two foreign parents, were considered "natural born" subjects. Nearly 100 years before the American Revolution, acts of Parliament extended the right to be counted as "natural born subjects" to children born abroad to an English father.
"History Has Its Eyes On You"
Despite what appears to be precedent in British common and statutory law, there has been significant debate among legal scholars over whether the Founders intended either or both to apply in this instance. Attempting to clarify this muddled debate, the First Congress, which included some of the Founding Fathers, passed the Naturalization Act of 1790, which expressly defines the term "natural born" to include those born abroad to US citizens.
Despite this early statutory language, there have been numerous questions about whether presidential candidates, and even sitting presidents, were eligible for the presidency. Franklin Roosevelt, Jr, once discussed as a potential candidate for the Democrats, was born in his parents' vacation home in New Brunswick, Canada. Senator Goldwater, the 1964 GOP standard bearer, was born in Arizona before it became a state. In 1968, Governor George Romney was a leading Republican candidate, and he was born to American parents living in Mexico. Senator McCain's "natural born" status came into question in 2008 because he was born in the Panama Canal Zone to American parents serving in the military.
"Wait For It"
This election cycle, Republican frontrunner Donald Trump, having previously questioned the legitimacy of President Obama's birth certificate, has repeatedly pointed out that Senator Cruz, one of his primary rivals, was born to a Cuban father and an American mother in Canada and may be ineligible for the presidency. Legal scholars from all sides of the political spectrum have attempted to argue one way or the other whether Senator Cruz is eligible for the nation's highest elected office. Congress could pass a law further clarifying the issue, and the federal courts could intervene. As have many other candidates before him, Senator Cruz is yet another stuck in the complicated, muddy constitutional question of whether he is a "natural born" citizen.