Beginning with his early political activism against Britain's imperial regulations in May 1774, Jay served in several official posts on behalf of the Patriot cause in the ensuing decade. Jay sat in both the First and Second Continental Congresses that convened in Philadelphia. Although a resistance leader, Jay favored reconciliation with Britain and was slow to embrace the movement for independence, but once the Declaration of Independence was adopted on 4 July 1776, Jay threw his full support behind the cause. In addition, Jay performed many invaluable duties on behalf of New York. He helped secure the defenses of the Hudson Valley and headed the Committee for Detecting Conspiracies. Jay went on to draft a constitution for the fledgling State of New York that was adopted by a convention in Kingston on 20 April 1777. While in Kingston, he officiated as the first Chief Justice of the New York Supreme Court. Jay then served in Philadelphia as President of the Continental Congress before taking up a new role as overseas diplomat in 1779.
New York's Provincial Congress appointed Jay as commander of the 2nd Regiment of the New York City Militia in November 1775. The officers serving in this unit included many of his close friends and associates. Jay was little more than a commander in name only, however, as he chose to work in politics and therefore saw no active service with the regiment. Nonetheless, he was sometimes referred to as "Colonel Jay" in later years.
Jay attended the Second Continental Congress in Philadelphia as part of the delegation from New York. Upon joining this body, Jay emerged as a leader of the moderate faction that opposed a final break with Britain. He demonstrated a commitment to reconciliation with the Crown by writing an early draft of the Olive Branch Petition that was addressed to King George III. Nevertheless, Jay eventually called for a separation from the British Empire and fully embraced the cause of independence.
Recognized for his eloquence and persuasiveness, Jay frequently took up his pen and authored addresses and petitions on behalf of the First and Second Continental Congress. These writings included his "Address to the People of Great Britain" (October 1774), letter to the "Oppressed Inhabitants of Canada (May 1775)," a draft of the Olive Branch Petition (June 1775), and this "Address to the People of Ireland" (July 1775).
Jay worked closely with George Washington during the Revolutionary conflict. The pair developed a friendship that was forged in war and based on mutual respect and recognition of one another's talents. Jay remained Washington's steadfast supporter throughout the conflict, even as various schemes were hatched to discredit Washington and have him removed from command. Their relationship continued into the post-Revolutionary era and Washington's presidency. Washington viewed Jay as a trustworthy confidante and regularly sought his advice on matters of state. After appointing Jay to serve as Chief Jutice of the Supreme Court, Washington asked Jay to share his views on the Federal judiciary and urged him to respond with “the freedom & frankness of friendship."
When Patriot fortunes were at a low ebb in late 1776, John Jay drafted an essay to rally the public to the American cause. This publication was approved by New York's Congress and was forwarded to the Continental Congress then meeting in Baltimore. In January 1777, Congress ordered that Jay's work be translated into German and distributed among the German-speaking inhabitants of the mid-Atlantic region. English-language reprints were produced in Philadelphia and Baltimore and circulated throughout the state. Jay's work shared the same objective as Thomas Paine's pamphlet The American Crisis, which came out at the same time. Both works are noted for their eloquence and persuasive style; whereas Paine relied on exhortation and emotion to convey his arguments, Jay swayed readers by using a more legalistic framework and also employed more religious explanations and imagery.
After serving as President of the Continental Congress for nearly a year, Jay left this post to embark on a diplomatic mission in Spain. Jay criticized the behavior of his congressional colleagues and probably welcomed the opportunity to leave Philadelphia and serve overseas. As he commented in April 1779, "There is as much intrigue in this State House as in the Vatican, but as little secrecy as in a Boarding School. It mortifies me on this Occasion to reflect that the Rules of Congress on the Subject of Secrecy which are far too general and perhaps for that Reason more frequently violated, restrain me from saying twenty things to you which ceased to be private."
Sarah Livingston Jay so admired the leadership and character displayed by George Washington that she requested a lock of his hair as a keepsake. As this letter shows, Washington honored her request.
While serving as a peace commissioner in France in 1783, Jay celebrated American independence by offering the following toasts on the Fourth of July. The toasts focus on the role of foreign allies in securing the Patriot victory and also touch on the theme of the sacrifices and suffering endured by American soliders and their families.
1. The United States of America, may they be perpetual
2. The Congress
3. The King & Nation of France
4. General Washington & the American Army
5. The United Netherlands & all the other free States in the world.
6. His Catholic Majesty & all other Princes & Powers who have manifested Friendship to America--
7. The Memory of the Patriots who have fallen for the Country--May kindness be shown to their Widows & Children
8. The French Officers & Army who served in America
9. Gratitude to our Friends & Moderation to our Enemies
10. May all our Citizens be Soldiers, & all our Sold[i]ers Citizens
11. Concord, Wisdom, & Firmness to all American Councils
12. May our Country be always prepared for War, but disposed to Peace
13. Liberty & Happiness to all Mankind--
Jay's intelligence activities with the Committee for Detecting Conspiracies served as an inspiration for James Fenimore Cooper's novel The Spy: A Tale of the Neutral Ground, first published in 1822. Cooper probably based the character of Harvey Birch, a Patriot secret agent, on the real life exploits of Enoch Crosby, a resident of Putnam County who posed as a Loyalist during the Revolutionary conflict and worked with Jay in keeping tabs on British agents and sympathizers operating in Westchester County.