John Adams was president when the treaty was ratified..
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.
Yes... that is true although he would still call himself a Christian... just a non-trinitarian Protestant Christian and as much declare the US Christian.
ADDED:
"As no truth is more clearly taught in the Volume of Inspiration, not any more fully demonstrated by the experience of all ages, than that a deep sense and a due acknowledgment of the growing
providence of a Supreme Being and of the accountableness of men to Him as the searcher of hearts and righteous distributor of rewards and punishments are conducive equally to the happiness of individuals and to the well-being of communities....I have thought proper to recommend, and I hereby recommend accordingly, that Thursday, the twenty-fifth of April next, be observed throughout the United States of America as a day of solemn humiliation, fasting, and prayer; that the citizens on that day abstain, as far as may be, from their secular occupation, and devote the time to the sacred duties of religion,
in public and in private; that they call to mind our numerous offenses against the most high God, confess them before Him with the sincerest penitence, implore His pardoning mercy,
through the Great Mediator and Redeemer, for our past transgressions, and that through
His Holy Spirit, we may be disposed and enabled to yield a more suitable obedience to
His righteous requisitions in time to come; that He would interpose to arrest the progress of that impiety and licentiousness in principle and practice so offensive to Himself and so ruinous to mankind; that He would make us deeply sensible that "
righteousness exalteth a nation, but sin is a reproach to any people" [Proverbs 14:34]."
John Adams, "National Fast Day," A COMPILATION OF THE MESSAGES AND PAPERS OF THE PRESIDENTS, 1:284-86.