I can't find any reference to this other than a letter from Roosevelt saying that LeLong elected to be a citizen and "Where an alien in good faith becomes a citizen, I would protect him in every way."
That's a far cry from stating that he's eligible to be President. Do you have any other sources that I could read?
-PJ
He wrote a book called “Fear God and Take Your Own Part (1916). Chapter 9 is titled “When is an American not an American?” He discusses Mr. P. A. LeLong who was born in New Orleans in 1880 to an alien father (citizen of France) and an American citizen mother. LeLong wrote to the Secretary of State William Jennings Bryan about whether on a trip to France, LeLong could be drafted into the French military. The State Department wrote back that as a dual citizen, he would be subject to French laws if he went there.
Roosevelt wrote about the LeLong case in a discussion of dual citizenship (he was opposed to it). On LeLong he wrote:
“Mr. LeLong was born in this country, when he became of age he elected to exercise his birthright granted to him by the Constitution of the United States; he took an oath to support that Constitution; and he has held military office under its authority, and under the authority of two states of the American Union. He is eligible to the Presidency of the United States. He is a citizen of the United States, …”