President John Adams was a devout Unitarian, which was a non-trinitarian Protestant Christian denomination during the Colonial era.
He was identified as a Congregationalist by The Congregationalist Library. 1995 Information Please Almanac was cited as the source stating he was a later a Unitarian. (Source: Ian Dorion, "Table of the Religious Affiliations of American Founders", 1997).
From: Peter Roberts, "John Adams" page in "God and Country" section of "Science Resources on the Net" website (http://www.geocities.com/peterroberts.geo/Relig-Politics/JohnAdams.html; viewed 23 November 2005):
Religious Affiliation: Unitarian
Summary of Religious Views:
Adams was raised a Congregationalist, but ultimately rejected many fundamental doctrines of conventional Christianity, such as the Trinity and the divinity of Jesus, becoming a Unitarian. In his youth, Adams' father urged him to become a minister, but Adams refused, considering the practice of law to be a more noble calling. Although he once referred to himself as a "church going animal," Adams' view of religion overall was rather ambivalent: He recognized the abuses, large and small, that religious belief lends itself to, but he also believed that religion could be a force for good in individual lives and in society at large. His extensive reading (especially in the classics), led him to believe that this view applied not only to Christianity, but to all religions.
Adams was aware of (and wary of) the risks, such as persecution of minorities and the temptation to wage holy wars, that an established religion poses. Nonetheless, he believed that religion, by uniting and morally guiding the people, had a role in public life.
From: B. J. Lossing, Signers of the Declaration of Independence, George F. Cooledge & Brother: New York (1848) [reprinted in Lives of the Signers of the Declaration of Independence, WallBuilder Press: Aledo, Texas (1995)], pages 27-28:
No loftier genius nor purer patriot wore the Senatorial robe during the struggle for Independence, than John Adams. He was born at Brainree (now Quincy), in Massachusetts, on the thirtieth of October, 1735, and was a direct lineal descendant, in the fourt generation, from Henry Adams, who fled from the persecutions in England during the reign of the first Charles. His maternal ancestor was John Alden, a passenger in the May-Flower, and thus the subject of our memoir inherited from both parental ancestors, the title of a Son of Liberty, which was subsequently given to him and others...From: B. J. Lossing, Signers of the Declaration of Independence, George F. Cooledge & Brother: New York (1848) [reprinted in Lives of the Signers of the Declaration of Independence, WallBuilder Press: Aledo, Texas (1995)], pages 2:
Archbishop Laud, the spiritual adviser of Charles I [from whom John Adams' ancestor fled] (influenced no doubt by the Roman Catholic Queen, Henrietta Maria) took especial plans to enforce the strictest observance of the Liturgy of the established Church of England in the Church of Scotland, and also in the Puritan Churches. Those individuals and congregations who would not conform to these requirements were severely dealt with, and these persecutions drove a greta many to the western world, where they might worship God according to the dictates of their own consciences.
In 1766 Mr. Adams [John Adams] married Abigail Smith, the amiable daughter of a pious clergyman [a liberal Congregationalist] of Braintree, and soon afterward he removed to Boston.From: Laurie Carter Noble, "Abigail Adams" article on Unitarian Universalist Historical Society website (http://www.uua.org/uuhs/duub/articles/abigailadams.html; viewed 13 November 2005):
Born in the parsonage of the North Parish Congregational Church of Weymouth to the Rev. William Smith and Elizabeth Quincy, Abigail was raised simply and without pretension, though her relatives, especially on her mother's side, were among the leading families of their time...From: Robert G. Ferris (editor), Signers of the Declaration: Historic Places Commemorating the Signing of the Declaration of Independence, published by the United States Department of the Interior, National Park Service: Washington, D.C. (revised edition 1975), page 35:
Her father, William Smith (1707-1783), was a liberal Congregationalist, who often exchanged pulpits with his friend, Ebenezer Gay. Smith was an Arminian. He did not preach the doctrines of predestination, original sin, or the full divinity of Christ. Rather, he emphasized the importance of reason and morality in religious life. This simple faith his daughter Abigail confessed when she was received into membership in the Weymouth church on June 24, 1759.
That same year, Abigail Smith met John Adams. By 1762 they were exchanging frankly affectionate love letters full of mischievous humor. Their wedding, on October 25, 1764, began one of history's great partnerships. They were lovers, friends, counselors, and mentors to one another into old age...
John and Abigail Adams were active members of the First Parish Church in Quincy, which was already unitarian in doctrine by 1753. Although she did not sign the membership book (John did), she attended the church, supported it, and showed active concern and care for its ministry. She is a celebrated figure in her congregation's tradition. Abigail's theology is clearly stated in her correspondence. Writing to her son, John Quincy Adams, on May 5, 1816, she said, "I acknowledge myself a unitarian -- Believing that the Father alone, is the supreme God, and that Jesus Christ derived his Being, and all his powers and honors from the Father." "There is not any reasoning which can convince me, contrary to my senses, that three is one, and one three." On January 3, 1818, writing to her daughter-in-law, Louisa, Abigail wondered "when will Mankind be convinced that true Religion is from the Heart, between Man and his creator, and not the imposition of Man or creeds and tests?" Like many early Unitarians she discounted sectarian claims and was "assured that those who fear God and work righteousness shall be accepted of him, and that I presume of what ever sect or persuasion."
Early in October, 1818, Abigail fell ill with typhus and died several weeks later. She was buried in the cemetery of First Church in Quincy. John Adams died in 1826 during the presidency of John Quincy Adams.
The Jeffersonians drove the Federalists out of office in 1800, and Adams retired to Quincy, where he spent his later years quietly... John [Adams] died at the age of 90 just a few hours after [Thomas] Jefferson, on July 4, 1826--dramatically enough the 50th anniversary of the adoption of the Declaration. Except for Charles Carroll, who was to live until 1832, Adams and Jefferson were the last two surviving signers. The remains of John and Abigail Adams are interred in a basement crypt at the United First Parish Church in Quincy.From: Rick Shenkman, "An Interview with Jon Butler ... Was America Founded as a Christian Nation?", posted 20 December 2004 on History News Network website (http://hnn.us/articles/9144.html; viewed 30 November 2005):
Mr. Butler, Dean of the Graduate School of Arts & Sciences at Yale University, is the author of Awash in a Sea of Faith: Christianizing the American People (Harvard University Press, 1990). This interview was conducted by HNN editor Rick Shenkman for The Learning Channel series, "Myth America," which aired several years ago...From: R.P. Nettelhorst, "Notes on the Founding Fathers and the Separation of Church and State", posted on Quartz Hill School of Theology website (http://www.theology.edu/journal/volume2/ushistor.htm; viewed 30 November 2005):
[Jon Butler:] The principal Founding Fathers--Washington, Jefferson, Adams, Franklin--were in fact deeply suspicious of a European pattern of governmental involvement in religion. They were deeply concerned about an involvement in religion because they saw government as corrupting religion. Ministers who were paid by the state and paid by the government didn't pay any attention to their parishes. They didn't care about their parishioners. They could have, they sold their parishes. They sold their jobs and brought in a hireling to do it and they wandered off to live somewhere else and they didn't need to pay attention to their parishioners because the parishioners weren't paying them. The state was paying them.
John Adams, the second U.S. President rejected the Trinity... and became a Unitarian. It was during Adams' presidency that the Senate ratified the Treaty of Peace and Friendship with Tripoli, which states in Article XI that:As the government of the United States of America is not in any sense founded on the Christian Religion - as it has in itself no character of enmity against the laws, religion or tranquility of Musselmen, - and as the said States never have entered into any war or act of hostility against any Mehomitan nation, it is declared by the parties that no pretext arrising from religious opinions shall ever produce an interruption of the harmony existing between the two countries. (Charles I. Bevans, ed. Treaties and Other International Agreements of the United States of America 1776-1949. Vol. 11: Philippines-United Arab Republic. Washington D.C.: Department of State Publications, 1974, p. 1072).This treaty with the Islamic state of Tripoli had been written and concluded by Joel Barlow during Washington's Administration. The U.S. Senate ratified the treaty on June 7, 1797; President Adams signed it on June 10, 1797 and it was first published in the Session Laws of the Fifth Congress, first session in 1797.