With the advent of the Second Party System, he allied with the National Republican (later Whig) Party and was a fervent supporter of Henry Clay and opponent of Democrats Andrew Jackson and Martin Van Buren. Jackson supporters in the Senate refused to confirm Crittenden's nomination by John Quincy Adams to the U.S. Supreme Court in 1828, but after his brief service as Kentucky Secretary of State, the state legislature elected him to the second of his four non-consecutive stints in the U.S. Senate. Upon his election as president, William Henry Harrison appointed Crittenden as Attorney General, but 5 months after Harrison's death, political differences prompted him to resign rather than continue his service under Harrison's successor, John Tyler.