A note to my post below. President William Howard Taft was a Unitarian, who disclosed that he "did not believe in the divinity of Christ." He was a moderate Progressive (versus the committed TR and Woodrow Wilson) and not a bad Chief Justice. William Jennings Bryan, the Democrat nominee in 1908, did object. It seems likely that the Christian fervor of TR's 1912 campaign ("Onward, Christian Soldiers" was a campaign song) was directed against Taft's faith.
Besides other Unitarian presidents (the Adamses), Vice President John C. Calhoun was also of this church. Again, the real measure of loyalty to basic American principles is understanding of and adherence to the Declaration of Independence.