You need to check your facts. All the men you listed considered themselves Christians.
Ben Franlin:
http://www.balaams-ass.com/journal/homemake/franklin.htm
Here's a couple of links on Washington:
http://www.virginiaplaces.org/religion/religiongw.html
http://www.infidels.org/library/historical/john_remsburg/six_historic_americans/chapter_3.html
Thomas Jefferson in a letter to John Adams:
"The day will come when the mystical generation of Jesus, by the Supreme Being as his father, in the womb of a virgin will be classed with the fable of the generation of Minerva in the brain of Jupiter" (Works, Vol. iv, p. 365).
Lincoln:
"Mr. Lincoln was never a member of any Church, nor did he believe in the divinity of Christ, or the inspiration of the Scriptures in the sense understood by evangelical Christians." (Col. Ward H. Lamon's Life of Lincoln, p. 486.)
Col. Lamon, a close friend and long-term associate of Lincoln, was himself a Christian, and considered Lincoln's lack of belief a defect of his otherwise great character.
While some argue the contrary, the evidence is pretty persuasive that these men were not in fact Christians.
More Lincoln lore:
"In 1846, when he was a candidate for Congress against a Methodist minister, the Rev. Peter Cartwright, his opponent openly accused him of being an unbeliever, and Lincoln never denied it. A story is told of Mr. Cartwright's holding a revival meeting while the campaign was in progress, during which Lincoln stepped into one of his meetings. When Cartwright asked the audience, "Will all who want to go to heaven stand up?" all arose except Lincoln. When he asked, "Now, will all who want to go to hell stand up?" Lincoln still remained in his seat. Mr. Cartwright then said, "All have stood up for one place or the other except Mr. Lincoln, and we would like to know where he expects to go." Lincoln arose and quietly said, "I am going to Congress," and there he went.
"On March 26, 1843, at the time Lincoln was attempting to obtain the nomination for Congress, he wrote to Martin M. Morris, of Petersburg, Ill.:"
"There was the strangest combination of church influence against me. Baker is a Campbellite; and therefore, as I suppose with few exceptions, got all of that Church. My wife had some relations in the Presbyterian churches, and some in the Episcopal churches; and therefore, wherever it would tell, I was set down as either one or the other, while it was everywhere contended that no Christian ought to vote for me because I belonged to no Church, was suspected of being a Deist and had talked about fighting a duel." (Complete Works of Abraham Lincoln, Nicolay & Hay edition, vol. 1, p. 80.)