Alexander Hamilton was a delegate to the Constitutional Convention. Along with John Jay and James Madison, Hamilton authored an important work, The Federalist Papers, that argued for ratification of the new Constitution. He brought to the convention his own draft version of a constitution, including qualifications for president that we look at here.
While it has been abundantly clear in my research that those born in the United States (except the children of ambassadors and invading armies, slaves, and the Indians) were always considered natural born citizens, there has been some question as to whether this extends to those who are citizens at birth by law (such as the children of citizens born overseas). Here we have a statement by a key figure in the debate, and very likely the source of the clause in the constitution we have today, that the intention of the framers, at least this one very influential framer, was that the qualification is “born a citizen”.
Hamilton’s draft constitution was presented late in the process of the convention. We know that the presidential eligibility clause citizenship requirement was also added late in the process.
This is what Hamilton’s draft constitution said:
Sec 1 No person shall be eligible to the office of President of the United States unless he be now a citizen of one of the States or hereafter be born a citizen of the United States.
This was cited by Jill Pryor in her important law review article, The Natural-Born Citizen Clause and Presidential Eligibility: An Approach for Resolving Two Hundred Years of Uncertainty, that is among the Obama Conspiracy Theories Bookmarks (link above) and my thanks goes to various blog posters including nolu chan on Politijab.com who highlighted it.