King was the informal de facto Federalist nominee for president in 1816, losing in a landslide to James Monroe. The Federalist Party became defunct at the national level after 1816, and King was the last presidential nominee the party fielded. Nonetheless, King was able to remain in the Senate until 1825, making him the last Federalist senator, due to a split in the New York Democratic-Republican Party. After that King accepted John Quincy Adams's appointment to serve another term as ambassador to Britain, but ill health forced King to retire from public life, and he died in 1827. King had five children who lived to adulthood, and he has numerous notable descendants.