Socialism was once a dirty word in U.S. politics, but some young progressives say it is the future of the Democratic Party. Here's everything you need to know:

Is this the socialist moment?
As the Democratic Party struggles to rise from the ashes of widespread electoral defeat, a growing number of progressives argue that the party can win back the working and middle classes only by moving to the left. This movement took its inspiration from the 2016 presidential candidacy of self-described democratic socialist Sen. Bernie Sanders (I-Vt.), and his full-throated repudiation of Wall Street and the business-friendly centrism of Hillary Clinton. One of Sanders' supporters, 28-year-old Alexandria Ocasio-Cortez, stunned the political world last month by winning her New York City district's Democratic primary on a platform of "Medicare for All," free public college, the abolition of ICE, and guaranteed work and housing. "In a modern, moral, and wealthy society, no person should be too poor to live," Ocasio-Cortez says. Democratic National Committee Chairman Tom Perez has called Ocasio-Cortez and other democratic socialist candidates "the future of our party."

What exactly is democratic socialism?
It depends on whom you ask. Sanders has said his brand of socialism differs from Marxism, which calls for government ownership and management of all private industry. He wants the U.S. to adopt the social democracy of Scandinavian countries like Denmark and Norway, where a robust social safety net operates in a regulated free-market economy. To pay for a similar safety net in the U.S., including free medical care and college education for all, Sanders would raise more than $1 trillion a year through higher taxes on most individuals and corporations. But the new guard of democratic socialists, organized under the banner of the Democratic Socialists of America (DSA), would go much further. Ocasio-Cortez, for example, has said she believes capitalism "will not always exist in the world."

What is the DSA?
It's a national political organization that traces its lineage back to Eugene Debs' Socialist Party from the early 20th century. Though still very small, the DSA has grown from 5,000 dues-paying members in 2015 to more than 45,000 members in about 180 local chapters today. DSA's national platform calls for abolishing capitalism, nationalizing the entire health-care industry, "economic planning," ending "the influence of money in politics," and restructuring "gender and cultural relationships to be more equitable." Many of the socialist principals advocated by the DSA already enjoy broad support among millennials, who lived through the fallout of the Great Recession, are still struggling with low salaries and piles of college debt, and are cynical about capitalism and the promise of "the American Dream." A 2016 Gallup poll found 55 percent of people between 18 and 29 said they had a positive view of socialism. "I already considered myself a socialist," says Amy Zachmeyer, now co-chair of the DSA's Houston chapter, "but didn't realize there were so many of us until Bernie Sanders kind of made it okay to talk about being a democratic socialist."

How popular is the DSA?
Four DSA-backed candidates recently won Pennsylvania state legislature primaries, and DSA says 35 of its members hold office in the U.S. But nearly all of them are at the city and county level, and in solidly liberal districts. In 2016, Sanders did mount a serious challenge to Clinton among Democratic voters, but has yet to show he can win over people who do not already define themselves as liberals or progressives. (In polls, about 25 percent of Americans say they are liberal.) If Ocasio-Cortez wins the general election in November, there will be just two democratic socialists in Congress. Sex and the City co-star Cynthia Nixon has embraced the "democratic socialist" label in her gubernatorial primary campaign versus Gov. Andrew Cuomo (D-N.Y.), but a recent poll has her trailing the center-left incumbent by 35 percentage points. In California, a democratic socialist running for lieutenant governor finished eighth, with 4 percent of the vote.

Is socialism the Democrats' future?
Thanks partly to Sanders' success, the party probably is headed to the left on such issues as the minimum wage, marijuana legalization, and health care. But most Democrats remain unwilling to embrace the socialist label. House Minority Leader Nancy Pelosi recently said Ocasio-Cortez's democratic socialism may be "ascendant in that district" — a very liberal swath of Queens and the Bronx — but argued that it wouldn't play in much of the rest of the country. "Our districts are very different," she said. Only 20 percent of Democrats say the party's ideology is "not liberal enough," according to a recent Economist/YouGov poll. Lanae Erickson Hatalsky of Third Way, a think tank that advocates centrist politics, recently studied "persuadable" voters who voted for Barack Obama and switched to Donald Trump, and found they take a dim view of progressive ideology, seeing it as anti-business and its proposals as handouts. "If the democratic socialists were able to take over the Democratic Party," Hatalsky says, "I think it would become a minority party for the next 10 to 20 years."

The price of democratic socialism
Few items on the democratic socialist wish list come with enough policy specifics to determine their true cost. One notable exception is Bernie Sanders' "Medicare for All" single-payer health-care proposal, which would eliminate private insurance and co-payments. Sanders has estimated the cost of his plan at about $1.4 trillion a year — a figure most analysts say is too low. The nonpartisan Urban Institute has calculated that single-payer health care would raise government spending by about $2.5  trillion a year over the current $3.8 trillion federal budget. Sanders and other proponents argue the cost would be lower, because national health care could produce large savings by cutting payment rates to doctors and hospitals, eliminating insurance costs, and requiring drug makers to charge lower prices. But even in the best-case scenario, national health care would require major tax increases affecting nearly all Americans. Sanders has proposed an additional 4 percent income tax on most individuals, a 7.5 percent tax on employers, and raising tax rates on a sliding scale for those earning over $250,000. His top tax rate would rise to 52 percent from 37 percent now.