View Full Record

Thomas Corwin

July 29, 1794 - December 18, 1865

Topic- U.S. Political Opposition to the War A Continent Divided: The U.S.-Mexico War

Thomas Corwin

July 29, 1794—December 18, 1865

A skilled orator and prominent Whig politician based in Ohio, Thomas Corwin served as governor of Ohio, as well as one of the state's U.S. senators. He gave a famous speech against the U.S.-Mexico War in February 1847—which propelled him to national fame—that denounced the war as unjust and predicted that territorial expansion would further divide the nation on the question of slavery.

Born in Bourbon County, Kentucky on July 29, 1794, Thomas Corwin's family migrated to the Northwest Territory, settling in what became Lebanon, Ohio. He took a job as an assistant in the Office of the Clerk of Court in 1814 and started studying law. He practiced law as a prosecuting attorney for Warren County until 1828.

His father, Matthias Corwin, served in the state legislature on several occasions. Consequently, Thomas Corwin participated in state politics, also serving in the legislature in the 1820s. In 1830, he was elected to the U.S. House of Representatives. He served five consecutive terms as a member of the Whig Party. He gave his first speech in Congress on April 4, 1834, and quickly garnered a reputation as a witty and articulate public speaker.

He resigned his seat in Congress in 1840 to capture the governorship of Ohio, which he held for two years. His governorship was largely tarnished by his unsuccessful attempt to create a state bank. The Ohio State Legislature subsequently elected him to the U.S. Senate in 1845. As a U.S. Senator, Corwin gained national prominence for opposing the U.S.-Mexico War.

When the war broke out in 1846, Corwin found himself opposing it primarily because of the territorial implications regarding slavery. The sectionalism dividing the nation at the time, he correctly predicted, would be enflamed by the question of slavery in the newly acquired territories. He believed that territorial expansion of the nation would be its undoing.

On February 11, 1847, Corwin gave a speech in the Senate against the war. He denounced the war for its expansionist motives, criticizing President Polk and his administration for misleading the public and Congress. He also distinguished himself from other anti-war members of Congress by asserting that he would no longer vote to fund the war. Although he did not persuade his colleagues in the Senate to join him, the press printed his speech and distributed it widely across the country. He briefly became popular among anti-slavery Whigs, and even entertained the prospect of seeking the party's nomination for the U.S. presidency. His unwillingness to fully embrace the abolition of slavery in principle, however, thwarted the possibility. He ended up campaigning for Zachary Taylor as a way to undermine the Free Soil movement and preserve the Whig Party as a national organization.

When the war ended in 1848, consistent in his views, Corwin denounced the Treaty of Guadalupe-Hidalgo for the land it ceded to the U.S. He remained convinced that a crisis over the future of slavery was quickly approaching. In 1850, President Millard Fillmore (President Taylor's successor) appointed Corwin secretary of the treasury.

Corwin briefly retired from politics in 1853 and re-established a law practice in Lebanon, Ohio. After the Whig Party dissolved in 1854, he joined the new Republican Party. He was once again elected to the U.S. House of Representatives in 1858, and campaigned for Abraham Lincoln in 1860.

President Lincoln appointed him minister to Mexico the following year. Corwin's commission was a particularly important one at the time, as the southern states were in revolt and shared a border with Mexico. Further complicating his assignment were European designs on Mexico. England and Spain pressed Mexico for reparations for its subjects, while France aimed to establish a puppet monarchy in Mexico. Corwin negotiated a treaty between the U.S. and Mexico (the Corwin-Doblado Treaty of April 6, 1862), which called for a U.S. loan to help Mexico pay its debts and expel the French. The U.S. Senate refused to ratify the treaty. Nevertheless, his tenure as minister in Mexico proved successful. His opposition to the U.S.-Mexico War made him well liked there, and positive U.S.-Mexico relations endured both countries' troubles in the 1860s.

Resigning his position, Corwin returned to the U.S. in 1864 and established a law practice in Washington D.C. He died there suddenly on December 18, 1865 after losing consciousness at a party held by notable Ohioans.


Corwin, Thomas. Life and Speeches of Thomas Corwin: Orator, Lawyer and Statesman. Edited by Josiah Morrow. Cincinnati: W. H. Anderson & Co., 1896.

Graebner, Norman A. "Thomas Corwin and the Election of 1848: A Study in Conservative Politics." The Journal of Southern History 17. May 1951.

Tucker, Spencer C. The Encyclopedia of the Mexican-American War: A Political, Social, and Military History. Santa Barbara: ABC-CLIO, 2012.

U.S. Mexico War logo