Young Frank Blair was a bright but difficult student, who was expelled from several private schools and later from the University of North Carolina and Yale. In 1841, he managed to complete his studies at Princeton, but faculty objections to his rude behavior postponed his graduation until the following year. In 1842, he attended law school at his father’s alma mater, Transylvania University in Lexington, Kentucky. After passing the bar, he joined his brother’s law firm in St. Louis, and then worked in the law office of Democratic Senator Thomas Hart Benton. In 1845, he traveled to the west in an effort to improve his health. At the commencement of the Mexican-American War, he enlisted in the army.  At the end of the war, he returned to St. Louis to resume his law practice and briefly edit the Missouri Democrat. He married Appoline Alexander; they had eight children.

Blair was a slaveowner, but opposed the expansion of slavery into the American West and favored the colonization of blacks to Africa. In 1848, he helped to found the Free-P in Missouri and edited the party’s organ, the Barnburner. His energetic condemnation of slavery and its expansion provoked an assassination attempt on his life. He did endorse, however, the Compromise of 1850, which allowed the electorates in the Utah and New Mexico territories to vote on the slavery issue and let California enter the Union as a free state. His stance on the 1850 Compromise led to a break with his political mentor, Senator Benton.

Blair represented the Democratic Party first in the Missouri legislature (1853-1856) and then in the U. S. Congress (1857-1859). He was the only Free-Soil advocate among slave-state congressmen, and he supported Republican John C. Frémont for president in 1856. His maiden speech on the House floor, partly written by his father, depicted slavery as a national problem, rather than as a regional institution. Arguing that slavery’s dissolution was inevitable, he advocated gradual emancipation and the colonization of free and freed blacks to Africa. In 1859, Blair gained national recognition for an anti-slavery speech (another collaboration with his father), in which the congressman articulated his plan of gradual emancipation, colonization, and free labor. The oration was published as The Destiny of the Races on This Continent.

In 1858, running as a Democrat, Blair lost his bid for reelection to Congress. In 1860, he became a Republican and after endorsing Missouri’s Edward Bates for the presidential nomination, switched at the national convention to back Abraham Lincoln. Blair campaigned vigorously for Lincoln in the general election and was himself elected by a narrow margin to Congress as a Republican. When the Southern slave states seceded and the threat of civil war mounted, Blair personally financed the organization of paramilitary units (called “Home Guards”) to defend St. Louis and Missouri for the Union. His home state was bitterly divided and became a bloody battleground during the Civil War. In the early months of the war, Blair led state militia units against Confederate troops before leaving to take his seat in Congress, where he chaired the House Committee on Military Defense. His actions in Missouri were instrumental in keeping that state within the Union.

Blair persuaded President Lincoln to name Frémont as Western Department commander, but the congressman soon became critical of what he considered to be Frémont's incompetence and lobbied for the general’s removal. In 1862, Blair resigned from Congress to take a commission in the Union army, and returned to Missouri where he used his own money to raise seven infantry regiments. After the siege of Vicksburg, Mississippi (March 29 – July 4, 1863), he was promoted to the rank of major general. He also saw action in the Chattanooga Campaign (October-November 1863) and in General William Tecumseh Sherman’s March to the Sea (November-December 1864). In 1862, Blair was reelected to Congress as a Republican, so resigned from the army to take his seat in the House on March 4, 1865.

In Congress, Blair backed the more lenient Reconstruction plans proposed by President Lincoln and, after Lincoln's assassination, by President Andrew Johnson, while he fought strenuously against the policies of the Radical Republicans. He so embittered his congressional colleagues that they rejected President Johnson’s nominations of him as revenue collector in St. Louis and as U.S. minister to Austria.

In 1868, the Democratic Party nominated Blair as Horatio Seymour’s vice-presidential running mate. During the campaign, Blair advocated nullification of the Reconstruction acts and predicted that if General Ulysses S. Grant, the Republican presidential nominee, were elected, his presidency would degenerate into a military dictatorship. Blair’s harsh words and abrasive personality tended to alienate potential supporters and provided fodder for his Republican opponents. He and Seymour lost the 1868 election.

In 1871, Blair won a special election to the U.S. Senate, supported by a coalition of Democrats and Liberal Republicans. In 1872, he campaigned for Horace Greeley, the presidential nominee of the Democratic and Liberal Republican Parties. Blair failed to win reelection to the Senate in 1873. Two years later, on July 8, 1875, he died in St. Louis of head injuries sustained in a fall.

Sources consulted: American National Biography; Biographical Directory of the U.S. Congress; Mark Boatner, The Civil War Dictionary.