Why did john c. calhoun resign from vice president

Calhoun held major political offices, serving terms in the United States House of Representatives, United States Senate and as theseventh Vice President of the United States (1825–1832), as well as secretary of war and state. He usually affiliated with theDemocrats, but flirted with the Whig Party and considered running for the presidency in 1824 and 1844. As a "war hawk", he agitated in Congress for the War of 1812 to defend American honor against Britain. Near the end of the war, he successfully delayed a vote on US Treasury notes being issued, arguing that the bill would not pass if the war were to end in the near future; the day of the vote, Congress received word from New York that the war was over. As Secretary of War under President James Monroe, he reorganized and modernized the War Department, building powerful permanent bureaucracies that ran the department, as opposed to patronage appointees and did so while trimming the requested funding each year.

I'm pretty sure that's called a volcano