Evidence suggests that, in the early 1960s, American college students favored pouring beer on their heads and dancing to “Louie Louie” over joining the Young People’s Socialist League (YPSL). But if anybody was likely to join the Socialist Party’s youth auxiliary, it was a brainy child of immigrant Jews, a son of Brooklyn — where Jewish voters had, for decades, cast ballots for socialists and liberals who resembled socialists.

For Bernie Sanders, socialism was something of a birthright.

Sanders began his political career under the tutelage of his older brother, Larry. President of Brooklyn College’s Young Democrats Club, Larry used to take Bernie to Manhattan’s Lower East Side to campaign against an urban renewal project that threatened to displace low-income residents.

It seems fitting that the country’s first serious socialist presidential candidate since the 1930s should have political roots in the Lower East Side — the cradle of New York socialism. Known as Kleindeutschland in the nineteenth century, the area’s German immigrants transplanted Karl Marx’s teachings to American soil and built a sturdy workers movement aligned with the Socialist Labor Party. Little Germany eventually gave way to “The Great Jewish Ghetto,” as more than five hundred thousand Yiddish-speaking immigrants streamed into the area.

The Jewish workers movement, modeled to a great extent on its German predecessor, grew into the largest, most powerful force in Jewish life. On any given day, Yiddish soapboxers dotted street corners and public squares. Political debates filled cafes and lecture halls. Escalating cycles of strikes and consumer boycotts fostered a culture of resistance.

Amid the ferment, socialism took shape, not so much as a doctrine, but a “whole climate of opinion that cemented, both economically and intellectually, a Jewish world in turmoil,” in the words of Moses Rischin, the Lower East Side’s pioneering historian.

New York socialism reached its political apex in the second decade of the twentieth century. In 1914, East Side voters sent labor lawyer and Socialist Party activist, Meyer London, to Congress. He was not America’s first Socialist congressman. That honor went to Milwaukee’s Victor Berger, an Austro-Hungarian Jew by birth. But London’s victory initiated a string of Socialist Party victories in New York. In 1917, the city’s predominantly Jewish precincts elected seven Socialist aldermen, ten state assemblymen, and a municipal judge to office.

“Du host gevunen /du host zikh aleyn gefunen,” the beloved Yiddish poet, Morris Rosenfeld, sang. “You have finally won / You have finally come into your own.”

Beyond New York, Americans of many backgrounds rallied around the Socialist Party. At its peak, the party counted almost 118,000 members across the country: native-born citizens, immigrants, blacks, whites, factory workers, farmers, and middle-class professionals. Debs garnered 6 percent of the popular vote in his 1912 presidential bid.

Socialists scored twelve hundred election victories and controlled a number of city governments, including those of Berkeley, Butte, Flint, and Milwaukee. The Kansas-based Socialist newspaper Appeal to Reason was for a time the most popular political weekly in the United States, with a peak circulation of 750,000.

And in the workplace, socialists controlled a number of important unions, including the Brewery Workers, the United Mine Workers, the International Association of Machinists, the International Ladies Garment Workers Union, the Amalgamated Clothing Workers of America, and other garment workers unions. That a cooperative commonwealth or a workers republic or some other vision of socialist society could be achieved in the near future seemed eminently possible in the early twentieth century.

Yet by the end of World War I the Socialist Party was in tatters. Its antiwar position invited formidable repression; at the New York State Assembly’s opening session in January 1920, the Speaker excoriated the Socialists as an organization of “aliens, enemy aliens, and minors.” The quintet had, he charged, been “elected on a platform that is absolutely inimical to the best interests of the state of New York and the United States.” The Assembly proceeded to suspend its five Socialist legislators by a vote of 140 to 6. Voters sent the five Socialists back to office nine months later, but three of them were again expelled. The other two resigned in solidarity.

Debates over the Soviet Union dealt another, arguably more damaging blow to the Socialist Party. In January 1919, the Communist International called on socialists everywhere to wage a “merciless” war against their own parties to purge moderate elements or, failing that, split from them. The Comintern wanted anticapitalists to form new revolutionary parties fearless enough to seize political power immediately and establish dictatorships of the proletariat.

In the wake of the October Revolution, the party’s left wing was energized. The SP’s national leadership expelled the leftists en masse in the summer of 1919. Some of them assembled in Chicago to establish a new, revolutionary party, but, unable to agree on a platform, they created two parties, both claiming the mantle of Russian communism. And, so, the American left was reconfigured. It would remain permanently divided between socialists and communists, and among communists themselves.

The Socialist Party showed a brief sign of revival with the onset of the Great Depression. Its presidential candidate, Norman Thomas, won almost 900,000 votes in 1932. But factionalism consumed the SP again. “Militants” agitated for revolution; Trotskyists attempted to bore from within; the social-democratic “Old Guard” pulled toward the Democrats. All the while, Thomas’s “centrists” tried in vain to hold the organization together.

Still, socialism as a political force persisted in certain cities. Milwaukee’s Socialist mayor, Frank Zeidler, served three terms between 1948 and 1960. And in New York, erstwhile Socialists formed the American Labor Party (ALP) in 1936, which wielded considerable clout thanks to New York’s fusion law, which enabled voters to cast their votes for one of the major parties though a third party.

Backed by the traditionally pro-Socialist garment unions and supported mainly by Jewish voters, the ALP and its successor, the Liberal Party, achieved major legislative gains for affordable housing, decent health care, civil rights, amenable labor laws, and access to the arts and education for working people. Social democracy triumphed in postwar New York like nowhere else in the United States.

Sanders came of age in the heyday of New York exceptionalism. To him, it seemed obvious that workers ought to use unions and the political system to transform society. He joined the Young People’s Socialist League as a student at the University of Chicago.

Founded in 1907, YPSL had little to show for itself by mid-century, but in the early sixties the country was changing. McCarthyism had lost credibility, Michael Harrington’s best-selling book, The Other America, brought poverty into popular conversation, and the Civil Rights Movement was on the march.

YPSL began to grow and its members played an outsized role in civil rights organizations, particularly in the North. Sanders became active in the Congress on Racial Equality and the Student Nonviolent Coordinating Committee, and participated in what is said to be Chicago’s first civil rights sit-in.

But if the 1960s began on a promising note, the 1970s witnessed the Socialist Party demise. Pulled apart by the Vietnam War, it collapsed in 1972, after 101 years of existence. By then, New York City was spiraling toward fiscal insolvency and social disorder, a national symbol of all that ailed America.

“Don’t you see,” pleaded Woody Allen’s character in Annie Hall, “the rest of the country looks upon New York like we’re left-wing, Communist, Jewish, homosexual pornographers? I think of us that way sometimes and I live here.”

What was a thirty-something New York Jewish socialist, who was not a pornographer, to do? Sanders moved to Vermont.

He hardly seemed poised to scale the heights of American politics. When he wasn’t trying his hand at carpentry or selling “radical film strips” to schools, Sanders ran for office five times unsuccessfully as a candidate for the Liberty Union Party. Yet, in 1983, at the height of the Reagan Revolution, when even liberalism became a dirty word, Sanders decided to run for office yet again.

But this time he won. Stranger still, Sanders was reelected twice and received national recognition as one of the country’s most effective mayors. And, as if to enter the realm of science fiction, Sanders was elected to the House of Representatives in 1990 and then the Senate in 2006.

How Bernie Sanders of Brooklyn became a credible candidate for the US presidency is something historians can puzzle over later. For the moment we can say that Sanders has accomplished no small achievement. He has restored the word “socialism” to American political discourse. The renewed vitality of the ideal may prove more significant, in the long term, than the election’s outcome.