action in the Sullivan Expedition against British-allied Iroquois on May 1779. Willett was made colonel of the 5th New York Regiment in early 1780, serving in the regiment until January 1, 1781, when it was disbanded. In April 1781, he was appointed as colonel of the Tryon County militia, with whom Willett secured a victory over a British-Indian force at Johnstown on October 25. After leading an aborted attempted to capture Fort Ontario, Willett's men disbanded themselves in 1783, bringing his military career to an end. Political career and death After the conflict's end, Willett returned to New York City and started working as a merchant. He subsequently aligned himself politically with the Anti-Federalist Party, including governor of New York George Clinton, to whom Willett served as a political advisor. Together, the pair frequently discussed plans to counter the political influence of the Democratic-Republican Party, which was dominated by politicians from the American South. In addition to being elected to the New York State Assembly in December 1783, Willett also twice served as the Sheriff of New York County. In 1790, George Washington, by now serving as the U.S. President, dispatched Willett as a diplomatic envoy to the Muscogee in order to persuade Alexander McGillivray, a prominent Muscogee leader, to come to New York City and negotiate with the federal government. Willett's mission was successful, and a delegation of twenty-seven Muscogee leaders led by McGillivray came to the city and negotiated the 1790 Treaty of New York with Washington and United States Secretary of War Henry Knox. The treaty delineated clear borders between American and Muscogee lands. Willett continued to advise the federal government on indigenous affairs after the treaty was signed. As noted by historian Colin G. Calloway, when tensions rose between encroaching settlers from Georgia and Muscogee tribals on the American frontier, Willett wrote a letter to Washington warning him against authorising a military offensive against the Muscogee without conducting a thorough investigation on the cause for the tensions. In the letter, Willett claimed that territorial ambitions from the "leading men of Georgia" were to blame for ongoing U.S. tensions with the Muscogee. In April 1792, Willett was appointed by Washington to command American forces in the ongoing Northwest Indian War at the rank of brigadier-general, though he did not accept the appointment. In a letter to Washington explaining his decision, Willett argued against the United States government's