Clayton, John Middleton, 1796–1856, American statesman, b. Sussex co., Del. Admitted (1819) to the bar, he practiced at Dover, Del., held many state offices, and was twice (1828, 1845) elected to the U.S. Senate. In the presidential election of 1848 he gave his support to Zachary Taylor and was rewarded with the position of Secretary of State, an office he held until Taylor's death in 1850. As Secretary of State he negotiated the Clayton-Bulwer Treaty Clayton-Bulwer Treaty, concluded (Apr. 19, 1850) at Washington, D.C., between the United States, represented by Secretary of State John M. Clayton, and Great Britain, represented by the British plenipotentiary Sir Henry Bulwer.
..... Click the link for more information. , which checked British expansion in Central America and temporarily settled a rivalry that had brought England and the United States into conflict. He reentered the Senate in 1852.

Clayton, John Middleton

(born July 24, 1796, Dagsboro, Del., U.S.—died Nov. 9, 1856, Dover, Del.) U.S. politician. He served as Delaware's secretary of state (1826–28) and chief justice (1837). He also represented Delaware in the U.S. Senate (1829–36, 1845–49). As U.S. secretary of state (1849–50) under Pres. Zachary Taylor, he negotiated the Clayton-Bulwer Treaty.

Clayton, John Middleton (1796–1856) U.S. senator, cabinet officer; born in Dagsboro, Del. He graduated from Yale (1815) and was admitted to the bar (1819). He served in the U.S. Senate (National Rep., Del.; 1829–36), then resigned to become chief justice of Delaware. He returned to the U.S. Senate (Whig, Del.; 1845–49), resigning again to serve as secretary of state under President Zachary Taylor (1849–50). His major achievement was to negotiate the so-called Clayton-Bulwer Treaty with Great Britain; it dispelled the increasing rivalry between the two nations in Central America by agreeing to a neutralized international canal in that region. Clayton resigned as secretary of state when Taylor died and returned to the U.S. Senate (1852–56).