Why did the framers of the Constitution require that a President be a natural born Citizen?

Answer 1

Because someone who was born in Another Country, even though they have become an American citizen, might still have sufficient regard or affection for their mother country to put it's interests above ours. Michael Montagne

And also, because the Founding Fathers wrote this into the Constitution. The people have the power to change this requirement, and any other part of the Constitution. This power belongs to the people alone. Changes to the Constitution are not made by the President, or Congress, or even the Supreme Court.

Answer 2

On July 25, 1787, John Jay wrote in a letter to George Washington,

"Permit me to hint, whether it would be wise and seasonable to provide 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." Essentially, it seemed to make sense that, if one thing should be required of the president, he should have been born in the United States. Perhaps, in that time, non-diplomatic migration was more likely to be seen as potentially treasonous.

In the intervening years, several thorny issues have arisen. Alexander Hamilton, for example, might have been president had he not been born on Nevis in the Caribbean. Indeed, some have suggested that the requirement was put in to keep Hamilton from becoming President. George Romney, a presidential candidate in 1968, had been born to American parents in Mexico; it might have been a larger issue if his candidacy had gotten further. In 2000 and then 2008, John McCain's candidacy was questioned by some because he had been born in the Panama Canal Zone to military parents.

The general consensus is that children born abroad to American parents are natural-born citizens (though there are Supreme Court cases directly contradicting each other on this matter). Naturalized citizens, however, do not qualify. Some have noted that it is odd that naturalized citizens may serve in most governmental offices, just not the presidency or vice presidency. Some have pointed out that problems could arise if the first couple of positions in the line of succession were vacated, and the next in line had not been a natural-born citizen. Multiple past secretaries of state, for example, have been naturalized (notably Henry Kissinger). It is unlikely that this will ever be an issue, but it's enough for constitutional scholars to get worked up over.