Hannibal Hamlin, American publisher and politician, 15th Vice President of the United States (d. 1891)

Hannibal Hamlin (August 27, 1809 – July 4, 1891) was an American attorney and politician from Maine. In a public service career spanning over 50 years, he served as the 15th vice president of the United States. The first Republican to hold the office, Hamlin served from 1861 to 1865. He is considered among the most influential politicians from Maine.

A native of Paris, Maine (part of Massachusetts until 1820), Hamlin managed his father's farm before becoming a newspaper editor. He studied law, was admitted to the bar in 1833, and began to practice in Hampden, Maine. Originally a Democrat, Hamlin began his political career with election to the Maine House of Representatives in 1835 and an appointment to the military staff of the Governor of Maine. As an officer in the militia, he took part in the 1839 negotiations that helped end the Aroostook War. Hamlin was elected twice to the United States House of Representatives, where he served from 1843 to 1847. In 1848 the state house elected him to the United States Senate, where he served until January 1857. He served as governor of Maine for six weeks in the beginning of 1857, after which he returned to the Senate. Hamlin was an active opponent of slavery; he supported the Wilmot Proviso and opposed the Compromise of 1850. In 1854, he strongly opposed passage of the Kansas–Nebraska Act. Hamlin's increasingly anti-slavery views caused him to leave the Democratic Party for the newly formed Republican Party in 1856.

In the 1860 election, Hamlin was the Republican nominee for vice president. Selected to run with Abraham Lincoln, who was from Illinois, Hamlin was chosen in part to bring geographic balance to the ticket and in part because, as a former Democrat, he could work to convince other anti-slavery Democrats that their future lay with the Republican Party. The Lincoln–Hamlin ticket was successful, and Hamlin served as vice president from 1861 to 1865, which included all but the last month of the American Civil War. The first Republican vice president, he held the office in an era when it was considered more a part of the legislative branch than the executive; he was not personally close to Lincoln and did not play a major role in his administration. Even so, Hamlin supported the administration's legislative program in his role as presiding officer of the Senate, and looked for other ways to demonstrate his support for the Union, including a term of service in a Maine militia unit during the war.

In the 1864 election, Hamlin was replaced as vice presidential nominee by Andrew Johnson, a Southern Democrat chosen for his appeal to Southern Unionists. After leaving the vice presidency, Hamlin served as Collector of the Port of Boston, a lucrative post to which he was appointed by Johnson after the latter succeeded to the presidency following Lincoln's assassination. Hamlin later resigned as Collector because of his disagreement with Johnson over Reconstruction of the former Confederate States of America.

In 1869, Hamlin was elected again to the U.S. Senate, and served two terms. After leaving the Senate in 1881, he served briefly as United States Ambassador to Spain before returning to Maine in late 1882. In retirement, Hamlin was a resident of Bangor, Maine, where he died in 1891. He was buried at Mount Hope Cemetery in Bangor.