John Isaac Guion

John Isaac Guion (November 18, 1802 – June 6, 1855) was an American politician from Mississippi who served as Governor in 1851.

Guion was born in Adams County. He studied law in Lebanon, Tennessee, was admitted to the bar, and established a successful practice in Vicksburg, Mississippi. He practiced in partnership with William L. Sharkey, and later with Seargent Smith Prentiss.

A Democrat in politics, Guion served in the Mississippi House of Representatives from 1842 to 1846. He later moved to Jackson, and was elected to the Mississippi Senate in 1848.

Guion supported slavery and states' rights. As a result, he played a prominent role in the Jackson convention of 1849, which was called to discuss hown the Southern states should respond to the possibility of California being admitted to the union as a free state.

In 1850 Guion was chosen to serve as the Senate's President pro tempore. In February 1851, Governor John A. Quitman resigned to defend himself against charges of aiding in filibustering expeditions against Spanish rule in Cuba. Guion became acting governor and served until November, when his Senate term expired. He had not run for reelection, and the Speaker of the Mississippi House had also not run for reelection. Since no one in the line of succession could assume the governorship, the legislature subsequently chose James Whitfield as an interim replacement, and he served until the term of the new governor started in 1852.

Guion had not run for reelection to the State Senate because he had run for judge of the Mississippi District Circuit Court in Jackson. He began his term as scheduled, and served until his death. He died on June 6, 1855 and was buried at Greenwood Cemetery in Jackson.