Actually, there
is something to the story about the Duke of York. It was never a true possibility, but the rumor
did exist at the time, and it caused a great big panic. Akhil Reed Amar - a prominent constitutional scholar actually wrote
an interesting article on the subject.
I quote from the article:
Several months before the Constitution was drafted, one prominent American politician, Confederation Congress president Nathaniel Gorham, had apparently written to Prince Henry of Prussia, a brother of Frederick the Great, to inquire whether the prince might consider coming to the New World to serve as a constitutional monarch. Though few in 1787 knew about this feeler, the summer-long secret constitutional drafting sessions in Philadelphia did fuel widespread speculation that the delegates were working to fasten a monarchy upon America. One leading rumor was that the bishop of Osnaburgh, the second son of George III, would be invited to become America's king.
The natural-born clause clearly gave the lie to such rumors and thereby eased anxieties about foreign nobility.
So the rumor mentioned in this thread did exist, and an offer to Henry of Prussia was
actually made (in fact, that offer likely caused the rumor about the Duke of York).
Of course, it wasn't just the rumor. While such (irrational) fears certainly existed at the time, the idea behind the 'natural born citizen' clause was really a far more general wish to guard against foreign influence. Keep in mind that at the time, many people in Europe still believed that the American 'experiment' would fail within a few years, and the Americans would come begging for some prince to be their new king. Many American politicians feared foreign powers would scheme against the Republic to 'help along' such a failure.
Dixit Alexander Hamilton: "
Nothing was more to be desired than that every practicable obstacle should be opposed to cabal, intrigue, and corruption. These most deadly adversaries of republican government might naturally have been expected to make their approaches from more than one quarter, but chiefly from the desire in foreign powers to gain an improper ascendant in our councils." He wrote that in the Federalist Papers, specifically in nr. 68, which is about the election of a president for the Republic. Washington's repeated urging for America to remain uninvolved in European schemes ("
trade with all nations; alliance with none") should be read in the very same context.
Bottom line: Americans feared foreign scheming (just how real this fear was at the time can be observed from the fact that the ridiculous rumor about the Duke of York caused a big panic), and they put up barriers against it. The 'natural born citizen' clause was one of those barriers.
If you want the clause out, though... eliminating the offer to prince Henry might actually be a goof start. That will prevent the Duke of York rumor, and that
might just be enough to help the clause be removed from the Constitution altogether.