Democratic candidates around the country now seek their blessing. Americans are joining their ranks by the thousands, rapidly expanding the group's membership rolls in just a few years.

And a sharply leftist political agenda that once produced eye rolls – on everything from their opposition to capitalism to their questioning the very existence of prisons – has become a serious topic of discussion on social media, and in mainstream political debate.

In short, it’s going according to a plan by the Democratic Socialists of America, a group that’s dedicated to pushing an anti-capitalist, socialist platform by infiltrating and working within the Democratic Party, and pushing it further and further to the left.

“Progressive and socialist candidates who openly reject the neoliberal mainstream Democratic agenda may choose for pragmatic reasons to use the Democratic Party ballot line in partisan races,” wrote Joseph M. Schwartz, vice chairman of the DSA, in the socialist Jacobin Magazine last August. “But whatever ballot line the movement chooses to use, we must always be working to increase the independent power of labor and the left.”

The Democratic Socialists playbook, detailed on its website, calls for a methodical march to becoming a truly national force – where they can run candidates and push ideas under a Socialist Party banner – by first working from within the Democratic establishment. That strategy paid off big with the recent congressional primary victory of Alexandria Ocasio-Cortez, a 28-year-old DSA member who much of the media has ordained the new face of the Democratic Party.

Ocasio-Cortez plans to stump for other Democratic primary candidates in the coming days, in Kansas and Michigan. Sen. Bernie Sanders, I-Vt., a self-described Democratic socialist, reportedly will join for one of the stops.

The DSA, which is not a formal political party but bills itself as the largest socialist organization in the U.S., is working its way into the Democratic Party in part because of its failure to advance its own brand with a voting public reflexively suspicious of hard-left socialist policies. So it set a goal of working with groups devoted to a wide range of issues like health care, college debt, immigration, and racism to see socialism – and Democratic Socialist political candidates – as the vehicle for policy changes.

“If we don’t relate politically to social forces bigger than our own, DSA could devolve into merely a large socialist sect or subculture,” wrote Schwartz and his co-author, Bhaskar Sunkara, founder of Jacobin Magazine.

The organization also has recognized it needs to broaden the diversity of its own membership, which it concedes is predominately white, male and upper-income.

“We will focus on overcoming this historic bias of our organization toward white (particularly male) activists. We will do this by building deeper ties with organizations representing poor and working-class women and people of color … We must do so with humility and take our lead from the organizations that organize and are led by poor and working-class people in those communities.”

Political experts say the soul searching is somewhat surprising.

“They seem very pragmatic, which to me doesn’t seem very Socialist,” said Daniel Pout, an instructor at Arizona State University’s School of Politics and Global Studies. “They have to almost be non-socialist in order to be popular.”

The DSA’s effort to push their causes through the Democratic political machine has met with success. Ocasio-Cortez has grabbed the headlines and broad media attention, but the DSA claims its candidates have won 22 of some 30 elections they took part in.

Whatever the numbers, it’s become trendy for Democratic Party candidates to align themselves with the Democratic Socialists. One of the more prominent examples is Cynthia Nixon, the former “Sex and the City” actress who is running against Gov. Andrew Cuomo in the New York Democratic gubernatorial primary.

Whatever [political party] ballot line the [socialist] movement chooses to use, we must always be working to increase the independent power of labor and the left. — Joseph M. Schwartz, vice chairman of the Democratic Socialists of America (DSA)

“It’s nice to see that our policies and what we espouse are resonating with people running for governor,” said Abdullah Younous, co-chair of DSA’s New York City chapter, to Politico. “The landscape is really shifting, and people are noticing it across the state.”

And the Democratic establishment, feeling the pressure to perform well in this year's midterm elections, doesn't seem terribly concerned about the DSA's efforts to push the party even further left.

"The DNC's mission is to elect Democrats from the school board to the oval office, and we welcome the help of all organizations to achieve that goal," said Sabrina Singh, deputy communications director for the Democratic National Committee. The DSA declined to comment for this article.

That leaves Democratic Socialists in a position to withhold their endorsement if a Democratic candidate isn’t far-left enough, posing a challenge to those who see the group as a vehicle to boost their chances of getting elected.

A flyer at a New York City DSA meeting to discuss whether to endorse Nixon was quoted by Politico as saying: “We don’t just grant endorsements to progressives who beg us for one. We endorse people who can advance the anti-capitalist struggle.”

DSA members say Democratic candidates must be willing to embrace policy positions like universal housing and health care, free public college education, shelter and transportation, the abolition of ICE, of the U.S. Senate, of prisons, and an economy where the worker is the priority. The DSA website also calls for everyone to receive a basic income -- whether or not they work.

The group has said it wants to move away from the image – though not all the tenets – of Marxist-Leninist principles. It does not want to be seen as a fringe group, so DSA-backed candidates frequently quote names like Martin Luther King, Jr. and Franklin D. Roosevelt, rather than Karl Marx or Vladimir Lenin.

Critics say they are determined to hit back at what they depict as a Marxist fox in Democratic sheep’s clothing. A large part of the Democratic Socialists’ growing support comes from younger voters who have no memory of the Cold War, and the more sinister threat and reputation of the Soviet Union and other Socialist states around the world.

“This is the tactic that Communist parties and socialist movements have used all over the world to gain influence in the political world,” said Marion Smith, executive director of the Victims of Communism Memorial Foundation, a Washington, D.C., nonprofit. “We saw that in Venezuela. They didn’t come to power as Communists, but that is what they were.”

Smith said the foundation teaches about authoritarian regimes that started out by downplaying or denying socialist or Communist leanings.

“Martin Luther King very explicitly considered viewing the Soviet Union and socialists as allies for civil rights in the U.S.,” Smith said. “But [ultimately] his great speeches, his call for civil rights, were a call for the American people to live up to the principles of the Declaration of Independence. It was an embrace of democratic values, not a rejection of them.”

Some Republicans across the country see opportunities to pick up critical swing votes if Democrats lurch too far left before November’s congressional elections.

“Democratic Socialism is a false paradise,” said Marc Molinaro, Dutchess County, N.Y., executive and front-runner for the Republican gubernatorial nomination. “What New Yorkers and Americans want is the ability to achieve success. Every American family deserves individual freedom, and the opportunity to achieve real success.”

“I don’t think New Yorkers or Americans want to embrace a party that hands over all aspects of our lives to a government that can barely provide services competently.”

Republicans believe they can also capitalize on issues like the Social Democrats’ call to abolish the ICE agency, which is picking up more support among more mainstream Democrats. Wisconsin Rep. Mark Pocan last week introduced legislation to abolish ICE, which led House Speaker Paul Ryan to say Democrats “have really jumped the shark on the left.”

Perhaps in response to the hard swing left among many candidates, some Democratic Party leaders asked Socialist candidates to tone down their anti-capitalist, pro-universal public benefits rhetoric. But emboldened Democratic Socialists don’t seem in the mood for compromise.

Democratic Socialist candidate Franklin Bynum, who in March won the Democratic nomination to be a Houston criminal court judge, simply refused Democratic Party leaders’ pressure to make his tone more mainstream. Bynum made clear the Democratic Party machine was useful to him, for now, given the limits of what he could achieve on the margins.

“If I have money, I will give them money because I can’t organize a get-out-the-vote campaign by myself,” he told the New York Times. “But I am focused more on building a movement than I am on helping Democrats get elected. My priority is reaching people who aren’t being spoken to at all.”

Pout, the Arizona professor, thinks socialists might someday have a chance at building enough support to run candidates of their own, under the Socialist Party banner.

"There’s an attack on the center, in both parties, on business-as-usual,” Pout said. “Jeff Flake, in my state, decided not to run again, he sees no way he can fight against this anti-establishment, anti-status-quo” environment.