Just outside Burlington, Vermont, is an intersection known as “the Five Corners,” the busiest in the state. Bernie Sanders considered it prime terra firma during his campaign for mayor of this handsome, sloping lakeside city in 1980. With his disheveled mop of gray locks blowing in the automobile exhaust, he would spend hours waving to the endless parade of passing motorists, many of whom honked and waved back. He won the election by 10—no misprint here—votes.

Born and raised in Brooklyn to a paint-salesman father who had emigrated from Poland and a homemaker mother, Sanders went off to the University of Chicago in 1960, where he took on a leading role in the burgeoning civil-rights movement. After graduation, he worked in a psychiatric hospital, taught with Head Start, and labored as a carpenter, eventually landing in the Green Mountain State in 1964, at the age of 23.

Sanders earned a reputation as a pragmatic and effective mayor and presided over an impressive economic transformation of the city (if you can call a population of 38,000 at the time a city), while insisting that housing remain affordable for lower-income residents. He often butted heads with local developers, who were over-eager to convert subsidized housing into luxury condos. “Over my dead body are you going to displace 366 working families,” Sanders once barked at a landlord.

After serving three terms as mayor of Burlington, Sanders set his sights on Congress, serving eight terms as the House’s sole independent socialist before moving shop over to the Senate in 2007. Despite Hillary Clinton’s claim that, unlike Sanders, “I’m a progressive who likes to get things done,” Sanders has been adept at getting amendments passed from his outpost, especially in his earlier years—of the 415 amendments Sanders has sponsored, 90 have passed, with 49 passing between 1995 and 2007, according to PolitiFact. But it was his eight-hour filibuster against the proposed extension of the Bush-era tax cuts in December 2010 that laid the groundwork for his 2016 presidential run. Petitions popped up all over the Internet urging him to run in 2012, and the text of his filibuster monologue was even published in book format under the title The Speech: A Historic Filibuster on Corporate Greed and the Decline of our Middle Class.