Evidence from the period right after the Constitutional Convention also supports the notion that the Founding Fathers were very concerned about foreign influence on the federal government, and in particular on the President.
The most direct evidence comes from a statement made by Charles Pinckney to the U.S. Senate in 1800. Pinckney had been a delegate to the Constitutional Convention and, on July 26, 1787, had been the first delegate to raise the issue of presidential qualifications in the debate. On March 25, 1800, the Senate was debating a bill "prescribing the mode of deciding disputed elections of President and Vice President of the United States."(54) Pinckney gave a detailed explanation for the Electoral College, emphasizing that the rules governing the Electoral College were designed so "as to make it impossible ... for improper domestic, or, what is of much more consequence, foreign influence and gold to interfere."(55)
Having a foreign born parent would cause undue influence.