Democratic presidential candidate Sen. Bernie Sanders, I-Vermont, speaks at George Washington University in Washington on Wednesday on his policy of democratic socialism, the economic philosophy that has guided his political career. Credit: Andrew Harnik | AP

WASHINGTON — Presidential candidate Bernie Sanders presented an expansive defense of democratic socialism on Wednesday, amplifying divisions among Democrats that some worry will hinder their push to defeat President Donald Trump and keep control of the House in 2020.

In an impassioned speech explaining his long-standing political philosophy, the independent senator from Vermont said, “Democratic socialism means to me requiring and achieving political and economic freedom in every community in this country.”

Sanders said he understood he would face “massive attacks from those who attempt to use the world ‘socialism’ as a slur.” He added: “I have faced and overcome these attacks for decades. And I am not the only one.”

The address, coming from a major presidential contender two weeks before the first Democratic debate, reflected a party that is in the midst of an internal battle to shape its identity ahead of the next election. Furthest to the left is Sanders, who has called for redrawing government in ways that magnify collective efforts, such as providing health care to all through a single-payer system and enacting a massive government-financed job creation effort.

No other presidential candidate has embraced a socialist platform. Sen. Elizabeth Warren, D-Massachusetts, has advocated taking on the economic system with every regulatory hammer she can seize, but she describes herself as a capitalist. Former Vice President Joe Biden and others have called for tinkering with the capitalist system to benefit more Americans.

The rise of Sanders and Rep. Alexandria Ocasio-Cortez, D-New York, also a democratic socialist, has caused friction with more traditional Democrats, including House Speaker Nancy Pelosi, D-California. Many Democratic candidates for president and Congress favor a less dramatic upheaval than what Sanders is advocating, but Republicans have nonetheless sought to tar all Democrats with the socialist label, including in a closely watched do-over election in North Carolina.

In the fights for Congress and the White House, the more moderate wing of the Democratic Party is hoping to reprise the strategy that helped the party win the House in 2018: focusing on suburban swing voters, using less drastic platforms.

“I’m a card-carrying capitalist,” said Rep. Matthew Cartwright, D-Pennsylvania, who represents a competitive district and supports Biden. He said it was unhelpful for Sanders to fixate on the democratic socialist label.

The views of Democrats such as Cartwright have gained traction in recent months, as evidenced by Biden’s position atop the polls, Sanders’ decline in recent surveys and Pelosi’s refusal to cave to demands from the most liberal Democrats to begin impeachment proceedings against Trump.

But Sanders, who is still running second in many surveys, has signaled that he intends to forcefully challenge those trends. In his 45-minute address at George Washington University, Sanders invoked the words of former President Franklin D. Roosevelt and the Rev. Martin Luther King Jr. as he drew a line between the global upheaval of the 20th century — including the rise of Nazi Germany — and the present day.

“The United States and the rest of the world face two very different political paths. On one hand, there is a growing movement toward oligarchy and authoritarianism,” Sanders said. “On the other hand, in opposition to oligarchy, there is a movement of working people and young people who in ever-increasing numbers are fighting for justice.”

Sanders, who gave a similar speech in 2015, has built his political movement on the pillars of enacting Medicare-for-all, creating tuition-free public colleges and universities, raising taxes on the wealthy and powerful and curbing the influence of large corporations. He cast his ideas as the “unfinished business” of the New Deal economic initiative pushed by Roosevelt.

“Not only did FDR’s agenda improve the lives of millions of Americans but the New Deal was enormously popular politically and helped defeat far-right extremism,” Sanders said. “For a time.”

Sanders is the only prominent candidate seeking the Democratic nomination who is not a Democrat. His speech could sharpen the contrast with Warren, who is increasingly battling Sanders for liberal voters.

It could also harden the distinctions between Sanders and Biden. Campaigning in Iowa on Wednesday, Biden sought to play down differences.

“I just think we’ve got a lot of really good candidates out there and making the case, and I don’t put a whole lot in terms of labels, Biden told reporters. “I just think that if you think about it, the vast majority of members who are running, the folks who were running now, are all kind of on the same page.” He said Sanders is “sincere about what he thinks, and I think he should go out and say it.”

While the FDR agenda mentioned by Sanders has proved to be lastingly popular, Trump and other Republicans have used socialism against modern-day Democrats by conjuring long-suffering countries such as Venezuela.

“So-called democratic socialism is nothing more than a Trojan horse, and it would destroy our country and destroy our way of life,” Sen. John Cornyn, R-Texas, said in a speech on the Senate floor. Cornyn is up for reelection in 2020.

As Cornyn made clear, a majority of the country remains cool to socialism. Less than half of Americans (47 percent) said they would vote for a qualified presidential candidate who is a socialist, according to a Gallup poll released in May. In an April Monmouth University poll, 57 percent said socialism is not compatible with American values.

Many Democratic campaign strategists have grown nervous about the impact of the party being seen as aligned with socialism. Democrats won back the House majority by flipping Republican-held seats in the moderate suburbs where they fear a backlash could imperil their standing in 2020.

“Republicans want to make this a labels debate. And a labels debate is tricky for Democrats,” Democratic pollster Nick Gourevitch said. But, he added, “Republicans being so focused on this leans directly into their greatest weakness, which is that Republicans are for the rich and powerful.”

Others are not alarmed. “I think history has already made this decision. When we did Social Security, it was socialist. When we did Medicare, it was socialist, and these are the most popular programs,” said Rep. Mark Pocan, D-Wisconsin, echoing some of Sanders’ arguments.

Some of Sanders’ lesser-known Democratic rivals are trying to attract attention by actively running against socialism. Former Colorado Gov. John Hickenlooper said “socialism is not the answer” at a recent speech in California, drawing boos from liberal activists.

Sanders’ ideology complicates his campaign in varied ways. His past comments about socialist and communist countries and his refusal to recognize opposition leader Juan Guaido as the interim leader of Venezuela, as the U.S. government and others have done, have alienated some Democrats.

And as many Democratic voters say they are judging the presidential candidates through the lens of how they would fare against Trump, Sanders’ views have raised questions about his electability.

On Wednesday, he argued that his vision of America presents an ideal contrast with Trump, whom he accused of engaging in and benefiting from “corporate socialism.” Sanders said that when “Trump screams socialism, all of his hypocrisy will not be lost on the American people.”

Washington Post writers Jenna Johnson, Mike DeBonis, Michael Scherer and Scott Clement contributed to this report.