Alben William Barkley (/ˈbɑːrkli/; November 24, 1877 – April 30, 1956) was the 35th vice president of the United States serving from 1949 to 1953 under President Harry S. Truman. In 1905, he was elected to local offices and in 1912 as a U.S. representative. Serving in both houses of Congress, he was a liberal Democrat, supporting President Woodrow Wilson's New Freedom domestic agenda and foreign policy.

Endorsing Prohibition and denouncing parimutuel betting, Barkley narrowly lost the Kentucky Democratic gubernatorial primary in 1923 to fellow representative J. Campbell Cantrill. In 1926, he unseated Republican senator Richard P. Ernst. In the Senate, he supported the New Deal approach to handling the Great Depression in the United States. Democrats chose him to succeed Senate Majority Leader Joseph Taylor Robinson upon Robinson's death in 1937. His 1938 re-election bid was an intense, bitter victory against Governor A. B. "Happy" Chandler. When World War II focused President Franklin D. Roosevelt's attention on foreign affairs, Barkley gained influence over the administration's domestic agenda. He resigned as floor leader after Roosevelt ignored his advice and vetoed the Revenue Act of 1943. The veto was overridden by both houses and the Democratic senators unanimously re-elected Barkley to the position of Majority Leader.

Barkley had a good working relationship with Senator Harry S. Truman, who became vice-president and then president in 1945. With Truman's popularity waning entering the 1948 Democratic National Convention, Barkley gave a keynote address that energized the delegates. Truman selected him as his running mate for the upcoming election, and the Democratic ticket scored an upset victory against Thomas Dewey and Earl Warren of the Republican Party. Barkley took an active role in the Truman administration, acting as its primary spokesman, especially after the Korean War required the majority of Truman's attention. When Truman announced that he would not seek re-election in 1952, Barkley began organizing a presidential campaign, but labor leaders refused to endorse his candidacy because of his age, and he withdrew from the race. He is the most recent Democratic vice president to never receive the party's presidential nomination. He retired but was coaxed back into public life, defeating incumbent Republican senator John Sherman Cooper in 1954. Barkley died of a heart attack on April 30, 1956.

Willie Alben Barkley, the eldest of eight children of John Wilson Barkley and Electa Eliza (Smith) Barkley, was born November 24, 1877. His grandmother, midwife Amanda Barkley, delivered him in the log house she lived in with her husband, Alben, in Wheel, Kentucky. Barkley's parents were tenant farmers who grew tobacco, and his father was an elder in the local Presbyterian church. Barkley traced his father's ancestry to Scots-Irish Presbyterians in Rowan County, North Carolina. Both parents were religious, opposed to playing cards and alcohol. Occasionally, Barkley's parents would leave him in the care of his grandparents for extended periods. During these times, his grandmother related stories of her relatives. Her childhood playmates included future U.S. Vice President Adlai Stevenson I and James A. McKenzie, a future U.S. representative from Kentucky.

Barkley worked on his parents' farm and attended school in Lowes, Kentucky, between the fall harvest and spring planting. Unhappy with his birth name, he adopted "Alben William" as soon as he was old enough to express his opinion in the matter. In the difficult economy of late 1891, relatives convinced Barkley's father to sell his farm and move to Clinton, to pursue opportunities as a tenant wheat farmer. Barkley enrolled at a local seminary school, but did not finish his studies before entering Marvin College, a Methodist school in Clinton that accepted younger students, in 1892. The college's president offered him a scholarship that covered his academic expenses in exchange for his work as a janitor. He allowed Barkley to miss the first and last month of the academic year to help on the family farm. Barkley was active in the debating society at Marvin. He earned a Bachelor of Arts degree in 1897, and his experiences at Marvin persuaded him to convert to Methodism, the denomination with which he identified for the rest of his life.

After graduation, Barkley went to Emory College (now part of Emory University) in Oxford, Georgia, the alma mater of several administrators and faculty members at Marvin. During the 1897–1898 academic year, he was active in the debating society and the Delta Tau Delta fraternity, but he could not afford to continue his education and returned to Clinton after the spring semester. He took a job teaching at Marvin College but did not make enough money to meet his basic living expenses. He resigned in December 1898 to move with his parents to Paducah, Kentucky, the county seat of McCracken County, where his father found employment at a cordage mill.

In Paducah, Barkley worked as a law clerk for Charles K. Wheeler, an attorney and congressman, accepting access to Wheeler's law library as payment for his services. Despite their political differences – Wheeler supported William Jennings Bryan and Free Silver, while Barkley identified with the Gold Democrats – he hoped that being acquainted with and taught by Wheeler would aid him in his future endeavors, but congressional duties frequently kept Wheeler away from the office. After two months, Barkley accepted an offer to clerk for Judge William Sutton Bishop and former congressman John Kerr Hendrick, who paid him $15 per month. He read law while completing his duties and was admitted to the bar in 1901. Barkley practiced in Paducah where a friend of Hendrick's appointed him reporter of the circuit court. He continued studying law in the summer of 1902 at the University of Virginia School of Law.

On December 19, 1904, Barkley declared his candidacy for county attorney of McCracken County well before the March 1905 Democratic primary. The Republicans did not nominate a candidate, so the Democratic primary was the de facto general election. Barkley faced two opponents in the primary – two-term incumbent Eugene A. Graves and Paducah Police Court Judge David Cross. He organized his own campaign and made speeches across the county, showcasing his eloquence and likeability. Graves received more votes than Barkley in Paducah, but McCracken County's rural farmers gave Barkley the victory, 1,525 votes to 1,096; Cross came in third with 602 votes. This was the only time Barkley ever challenged an incumbent Democrat.