What policy is senator John C. Calhoun most likely closely associated?

Senator John C. Calhoun is most closely associated with the policy of states' rights, which emphasizes the authority and autonomy of individual states over the federal government. He was a strong advocate for the protection of slavery and argued that states should have the right to nullify Federal Laws they deemed unconstitutional. Calhoun's beliefs played a significant role in the political landscape leading up to the Civil War, as he championed the interests of the South against perceived northern aggression.