When a thousand socialists from across the United States gathered in Chicago over the weekend for the biennial convention of Democratic Socialists of America, DSA National Director Maria Svart declared, “What we’re seeing today is historic: the largest gathering of democratic socialists in an era.”

Since the 2016 election, Svart is delighted to report, “tens of thousands of democratic socialists have come together to build a future for this country in which everyone has the right to a decent job, a good home, a free college education for their children, and health care for their family. For years, we’ve been sold hope and promised change by Wall Street politicians—now we’re taking matters into our own hands.”

DSA got a big boost from the surge of interest in democratic socialism that grew from the Sanders campaign. Bernie upended decades of right-wing histrionics, Democratic Party caution, and media neglect that bordered on malpractice when he showed America that a national contender could embrace the “S” word and survive. “Do they think I’m afraid of the word? I’m not afraid of the word,” declared Sanders as he launched his bid for the Democratic nomination. “When I ran for the Senate the first time, I ran against the wealthiest guy in the state of Vermont. He spent a lot on advertising—very ugly stuff. He kept attacking me as a liberal. He didn’t use the word ‘socialist’ at all, because everybody in the state knows that I am that.”

Rather than getting harmed for making an effort to explain how democratic socialism works in places like Denmark, Sanders benefited from the fact that he wasn’t just another apologist for the capitalist experiment that has produced market instability, cruel austerity, and scorching income inequality. In particular, young people were excited about alternatives.

DSA invited them into the fold—with a smart “continuing the political revolution” message that built on the slogan of the Sanders run—and thousands joined. The group’s membership has tripled over the past year—to 25,000—and it now has 177 local groups in 49 states and the District of Columbia. DSA members are running for local offices and winning across the country.

That’s a striking development in a country where—because of the often irrational responses of media and political elites—major public-policy challenges go unaddressed because of the rejection of sound responses that are deemed too “socialistic.” This has happened even with proposals for smart social and industrial strategies that have been successfully deployed in countries with which the United States is closely allied.

The prospect of democratic socialism in the United States might seem radical to some, but it is important to remember that it’s not a new one.

American socialists once governed great cities, helped to define the politics of states across the country, and played a critical role in setting the national agenda. The Socialist Party of Eugene Victor Debs and Norman Thomas influenced presidents and Congresses, and was covered on the front pages of newspapers on a daily basis.

That party had many bases of strength, and indeed exists to this day, along with DSA, Socialist Alternative, and an array of other socialist organizations, some old and some new.

From 1910 to 1960, the “hotbed of socialism” in America was Milwaukee, Wisconsin. At the time it was one of the largest and most prosperous cities in America—and it was run by Socialists. The first member of the Socialist Party to govern a major American city, Emil Seidel, took charge of Milwaukee in 1910, with the poet Carl Sandburg as his aide. Two years later, he ran for the vice presidency on a Socialist ticket headed by Debs. The Debs-Seidel ticket pulled close to 1 million votes nationally—6 percent of the total cast in an election year that saw Democrat Woodrow Wilson, “Bull Moose” Progressive Teddy Roosevelt, and even Republican William Howard Taft borrow ideas from the Socialists. By the end of 1912, the Socialist Party had elected mayors, city councilors, school-board members, and other officials in 169 cities from Butte, Montana, to New York City. In several states, it was so successful that it was no longer seen as a “third” or “minor” party.

In Wisconsin, for instance, Republicans held the majority of state legislative seats during the 1910s and 1920s, while Socialists usually formed the major opposition caucus. Democrats were an afterthought. When those legislatures ushered in many of the reforms that would define Wisconsin as America’s “laboratory of democracy,” progressive Republicans associated with Robert M. La Follette worked with the Milwaukee Socialists to advance the agenda.

The Milwaukee Socialists did not just influence Madison, Wisconsin, but Washington, DC, as well. The first Socialist elected to the US Congress, Milwaukeean Victor Berger, took his seat in 1911 and held it, on and off, until 1929. Far from being marginalized, Berger worked closely with the “insurgent” Republican caucus that included La Follette, New York Congressman Fiorello La Guardia, and the great progressive leaders of the era.

When La Follette mounted an independent progressive campaign for the presidency in 1924, the Socialist Party endorsed his candidacy and Debs hailed his calls for supporting public ownership of utilities, strengthening labor unions, protecting the rights of women and minorities, defending civil liberties, and preventing wars and war profiteering.

La Follette carried Wisconsin, finished second in 11 Western states, and won more than 5 million votes nationwide (17 percent of the total). When some comrades questioned endorsing a lifelong Republican, the Socialist mayor of Milwaukee, Daniel Hoan, said of La Follette: “He says the supreme issue is whether the wealth of the nation shall remain in the hands of the privileged few.… Is not that the thing we have been ding-donging for 40 years?”

The Socialist Party faded as a national force after Franklin Delano Roosevelt’s New Deal stole many of its ideas and much of its thunder. But democratic socialism never disappeared from the American landscape.

Seventy years after Emil Seidel took charge of Milwaukee with a declaration that “socialists are prepared to govern,” Bernie Sanders took charge of Burlington, Vermont, as a proud democratic socialist.

Sanders went on to serve as an independent socialist member of the US House and the US Senate, caucusing with Democrats but positioning himself to their left on issues ranging from health-care reform to trade to economic democracy.

His presidential candidacy demonstrated the appeal of these politics in the 21st century, which has been characterized by rampant inequality and the corrupt excesses of crony capitalism.

The growth of DSA confirms that the appeal of democratic socialism extends far beyond any one campaign—as do a recent American Culture & Faith Institute poll indicated. The survey found that 37 percent of all American adults now say they prefer socialism to capitalism. A 2016 Harvard University survey revealed that 51 percent of Americans aged 18 and 29 say they reject capitalism outright.

It is this search for economic and political alternatives that has given DSA an opening, not just to build its membership but to pressure the Democratic Party to move left.

“In the early 1900s, Eugene Debs and the Socialist Party rose in a grassroots movement against the forces of nationalism, oligarchy, and authoritarianism,” recalls DSA’s Svart. “One hundred years later, today’s democratic socialists stand in that same tradition, at a time no less perilous.”