Here is a taste of my plot line so far:
On Providence cite:
1) Hamilton's The Farmer Refuted
Good and wise men, in all ages, have...supposed, that the deity, from the relations, we stand in, to himself and to each other, has constituted an eternal and immutable law, which is, indispensibly, obligatory upon all mankind, prior to any human institution whatever.
[T]he supreme being gave existence to man, together with the means of preserving and beatifying that existence. He endowed him with rational faculties, by the help of which, to discern and pursue such things, as were consistent with his duty and interest, and invested him with an inviolable right to personal liberty, and personal safety.
The sacred rights of mankind are not to be rummaged for, among old parchments, or musty records. They are written, as with a sun beam, in the whole volume of human nature, by the hand of the divinity itself; and can never be erased or obscured by mortal power.
2) On morality being the central purpose of religion cite Ben Franklin's “Dialogue between Two Presbyterians,” April 10, 1735.
"Morality or Virtue is the End, Faith only a Means to obtain that End: And if the End be obtained, it is no matter by what Means."
–- “Dialogue between Two Presbyterians,” April 10, 1735.
Every religion consists of moral precepts, and of dogmas. In the first they all agree. All forbid us to murder, steal, plunder, bear false witness &ca. and these are the articles necessary for the preservation of order, justice, and happiness in society. In their particular dogmas all differ; no two professing the same....Among the Mahometans we are told that thousands fell victims to the dispute whether the first or second toe of Mahomet was longest; and what blood, how many human lives have the words ‘this do in remembrance of me’ cost the Christian world!…We see good men in all religions, and as many in one as another. It is then a matter of principle with me to avoid disturbing the tranquility of others by the expression of any opinion on the [unimportant points] innocent questions on which we schismatize, and think it enough to hold fast to those moral precepts which are of the essence of Christianity, and of all other religions.
–- Thomas Jefferson to James Fishback, Sept. 27, 1809
And maybe Washington's Farewell Address:
…Of all the dispositions and habits which lead to political prosperity, Religion and morality are indispensable supports....Whatever may be conceded to the influence of refined education on minds of peculiar structure, reason and experience both forbid us to expect that National morality can prevail in exclusion of religious principle.
3) On the Founders' ecumenicism (all religions leading to the same God). Four good ones from John Adams.
It has pleased the Providence of the first Cause, the Universal Cause, that Abraham should give religion not only to Hebrews but to Christians and Mahomitans, the greatest part of the modern civilized world.
–- John Adams to M.M. Noah, July 31, 1818.
Where is to be found Theology more orthodox or Phylosophy more profound than in the Introduction to the Shast[r]a [a Hindu Treatise]? “God is one, creator of all, Universal Sphere, without beginning, without End. God Governs all the Creation by a General Providence, resulting from his eternal designs. — Search not the Essence and the nature of the Eternal, who is one; Your research will be vain and presumptuous. It is enough that, day by day, and night by night, You adore his Power, his Wisdom and his Goodness, in his Works.”
–- John Adams to Thomas Jefferson, December 25, 1813.
θεμις was the goddess of honesty, justice, decency, and right; the wife of Jove, another name for Juno. She presided over all oracles, deliberations, and councils. She commanded all mortals to pray to Jupiter for all lawful benefits and blessings. Now, is not this (so far forth) the essence of Christian devotion?
-- John Adams to Thomas Jefferson, October 4, 1813.
I believe with Justin Martyr, that all good men are Christians, and I believe there have been, and are, good men in all nations, sincere and conscientious.
-– To Samuel Miller, July 8, 1820.
One from Franklin:
Both house and ground were vested in trustees, expressly for the use of any preacher of any religious persuasion who might desire to say something to the people at Philadelphia; the design in building not being to accommodate any particular sect, but the inhabitants in general; so that even if the Mufti of Constantinople were to send a missionary to preach Mohammedanism to us, he would find a pulpit at his service.
That was taken from his autobiography.
You should also mention that as Presidents, when Washington, Jefferson and Madison spoke to unconverted Native Americans they addressed God as "the Great Spirit," exactly as the Natives did.
This is even further removed from orthodox Christianity than praying to "Allah" because at least Allah claims to be the God of Abraham, while the Great Spirit makes no such claim.
See GW, TALK TO THE CHEROKEE NATION, City of Philadelphia, August 29, 1796;
To THE CHIEFS AND WARRIORS, REPRESENTATIVES OF THE WYANDOTS, DELAWARES, SHAWANOES, OTTAWAS, CHIPPEWAS, POTAWATIMES, MIAMIS, EEL RIVER, WEEAS, KICKAPOOS, PIANKASHAWS, AND KASKASKIAS, Philadelphia, November 29, 1796.
See TJ, Address to Indian Nations, 1802.
See JM, "To My Red Children," August 1812.
4) Jesus as not God.
The Trinity was carried in a general council by one vote against a quaternity; the Virgin Mary lost an equality with the Father, Son, and Spirit only by a single suffrage.
-- John Adams to Benjamin Rush, June 12, 1812.
An incarnate God!!! An eternal, self-existent, omnipresent omniscient Author of this stupendous Universe, suffering on a Cross!!! My Soul starts with horror, at the Idea, and it has stupified the Christian World. It has been the Source of almost all of the Corruptions of Christianity.
-- John Adams to John Quincy Adams, March 28, 1816.
If I understand the Doctrine, it is, that if God the first second or third or all three together are united with or in a Man, the whole Animal becomes a God and his Mother is the Mother of God.
It grieves me: it shocks me to write in this stile upon a subject the most adorable that any finite Intelligence can contemplate or embrace: but if ever Mankind are to be superior to the Brutes, sacerdotal Impostures must be exposed.
-- John Adams to Francis van der Kemp, October 23, 1816.
No historical fact is better established, than that the doctrine of one God, pure and uncompounded, was that of the early ages of Christianity; and was among the efficacious doctrines which gave it triumph over the polytheism of the ancients, sickened with the absurdities of their own theology. Nor was the unity of the Supreme Being ousted from the Christian creed by the force of reason, but by the sword of civil government, wielded at the will of the fanatic Athanasius. The hocus-pocus phantasm of a God like another Cerberus, with one body and three heads, had its birth and growth in the blood of thousands and thousands of martyrs....In fact, the Athanasian paradox that one is three, and three but one, is so incomprehensible to the human mind, that no candid man can say he has any idea of it, and how can he believe what presents no idea? He who thinks he does, only deceives himself. He proves, also, that man, once surrendering his reason, has no remaining guard against absurdities the most monstrous, and like a ship without a rudder, is the sport of every wind. With such persons, gullibility which they call faith, takes the helm from the hand of reason, and the mind becomes a wreck.
-- Thomas Jefferson to Rev. James Smith, December 8, 1822.
For Franklin, cite his milder unitarianism that tolerated the Trinity as a harmless irrationality.
As to Jesus of Nazareth, my Opinion of whom you particularly desire, I think the System of Morals and his Religion as he left them to us, the best the World ever saw, or is likely to see; but I apprehend it has received various corrupting Changes, and I have with most of the present Dissenters in England, some Doubts as to his Divinity: tho' it is a Question I do not dogmatise upon, having never studied it, and think it needless to busy myself with it now, when I expect soon an Opportunity of knowing the Truth with less Trouble. I see no harm however in its being believed, if that Belief has the good Consequence as probably it has, of making his Doctrines more respected and better observed, especially as I do not perceive that the Supreme takes it amiss, by distinguishing the Believers, in his Government of the World, with any particular Marks of his Displeasure.
-- Ben Franklin to Ezra Stiles, March 9, 1790.
I think we have enough with this; we could note Washington's and Madison's silence on orthodox doctrines. We could quote Washington's minister on how he wasn't a "real Christian" because he systematically avoided communion (suggesting he disbelieved in the atonement). We could also quote George Ticknor (founder of the Boston public library) testifying that James Madison was a closet unitarian. It may be too much.
Adams and Jefferson kept their anti-Trinitarian secret; the point we should drive home is not so much the FFs' political theology was "anti-Trinitarian," given many Trinitarian FFs and in the populace. But rather there was no way in Hell these unitarians in high positions of power were going to let Trinitarianism infect their national Founding politics.