Bernard Sanders (born September 8, 1941) is an American politician serving as the senior United States senator from Vermont, a seat he has held since 2007. He was the U.S. representative for the state's at-large congressional district from 1991 to 2007. Sanders is the longest-serving independent in U.S. congressional history. He has a close relationship with the Democratic Party, having caucused with House and Senate Democrats for most of his congressional career. A self-described democratic socialist, he is often seen as a leader of the progressive movement in the United States. Sanders unsuccessfully sought the Democratic Party nomination for president of the United States in 2016 and 2020, finishing in second place in both campaigns. Before his election to Congress, he was mayor of Burlington, Vermont.

Born into a working-class Jewish family and raised in the Brooklyn borough of New York City, Sanders attended Brooklyn College before graduating from the University of Chicago in 1964. While a student, he was a protest organizer for the Congress of Racial Equality (CORE) and the Student Nonviolent Coordinating Committee (SNCC) during the civil rights movement. After settling in Vermont in 1968, he ran unsuccessful third-party political campaigns in the early to mid-1970s. He was elected mayor of Burlington in 1981 as an independent and was reelected three times. He won election to the U.S. House of Representatives in 1990, representing Vermont's at-large congressional district, later co-founding the Congressional Progressive Caucus. He served as a U.S. representative for 16 years before being elected to the U.S. Senate in 2006, notably becoming the first non-Republican elected to the seat in 152 years. Sanders was reelected to the Senate in 2012 and 2018. He chaired the Senate Veterans' Affairs Committee from 2013 to 2015 and the Senate Budget Committee from 2021 to 2023. In January 2023, he became chair of the Senate Health, Education, Labor and Pensions Committee, and the senior senator and dean of the Vermont congressional delegation upon Patrick Leahy's retirement from the Senate.

Sanders was a major candidate for the Democratic presidential nomination in 2016 and 2020, receiving the second most votes in each. Despite initially low expectations, his 2016 campaign generated significant grassroots enthusiasm and funding from small-dollar donors, carrying him to victory against eventual nominee Hillary Clinton in 23 primaries and caucuses before he conceded in July. In 2020, his strong showing in early primaries and caucuses made him the front-runner in a historically large field of Democratic candidates. In April 2020, Sanders conceded the nomination to Joe Biden, who had won a series of decisive victories as the field narrowed. He supported both Clinton and Biden in their respective general election campaigns against Donald Trump.

Sanders is credited with influencing a leftward shift in the Democratic Party after his 2016 presidential campaign. An advocate of social democratic and progressive policies, he is known for his opposition to economic inequality and neoliberalism. On domestic policy, he supports labor rights, universal and single-payer healthcare, paid parental leave, tuition-free tertiary education, and an ambitious Green New Deal to create jobs addressing climate change. On foreign policy, he supports reducing military spending, pursuing more diplomacy and international cooperation, and putting greater emphasis on labor rights and environmental concerns when negotiating international trade agreements. Sanders supports workplace democracy, and has praised elements of the Nordic model. Some have compared his politics to left-wing populism and the New Deal policies of President Franklin D. Roosevelt.