For the second time in four years, progressive voters’ hopes to elevate Senator Bernie Sanders of Vermont to the top of the Democratic ticket were dashed this spring, when Sanders’ call for a social revolution and Medicare for All fell flat, and former Vice President Joe Biden surged to victory in the race for the presidential nomination. In 2016, many of these same liberal Democrats decided to sit out the general election after Hillary Clinton edged out Sanders for the Democratic presidential nomination – and Sanders appeared half-hearted in urging them to back Clinton at the polls.  But Sanders made a compelling argument Monday night – at the start of the 2020 Democratic National Convention – that progressives’ issues and policies will live on if they help the more moderate Biden defeat President Donald Trump in the November 3 general election.  “The future of our democracy is at stake,” Sanders said in a live speech from his home in Burlington, Vermont. He added, “Many of the ideas we fought for, that just a few years ago were considered radical, are now mainstream.” The appeal for party unity was a departure for the self-styled democratic socialist who was the last remaining primary rival to Biden earlier this year. Sanders has not always advocated loyalty to the Democratic party, with whom he usually caucuses in the U.S. Senate.  Progressive wing He is seen foremost as the leader of the progressive wing of the Democratic Party, the group of liberal voters who support social reform policies intended to help working Americans, including universal health care, free college tuition, a higher minimum wage and a raft of other social benefits. Sanders rested his appeal to his supporters on the idea that defeating Trump is key to keeping progressive causes in the mainstream discussion.  FILE – Democratic presidential candidate former Vice President Joe Biden and his running mate Senator Kamala Harris, D-Calif., August 12, 2020.“I think he successfully showed that he’s strongly supporting Joe Biden and [vice presidential candidate Kamala] Harris, that he made the case to his movement that many of the issues that he was pushing now are mainstream and that he’s willing to work with progressives and, of course, moderates and even conservatives to help get Biden elected,” James Thurber, distinguished professor in the department of government at American University, said. He was referring to Biden’s running mate, California Senator Kamala Harris. Sanders’ conciliatory tone this year marks a departure from the 2016 election cycle, when he accused the Democratic Party of rigging the nomination process in favor of Clinton, and there was plenty of sniping between the Sanders and Clinton camps.  “This is a time where we’ve seen Senator Sanders be more of a party team player than he usually is. And I think it was quite impressive to many who were watching that he stayed on message,” said Lara Brown, director of the Graduate School of Political Management (GSPM) at the George Washington University. “Part of the case that he made last night was that the progressive agenda has really come more and more into the mainstream over the past few years and that that isn’t going to go away anytime soon,” Brown said.  But progressives’ values could be jeopardized, Sanders told supporters, unless they vote for Biden to ensure Trump does not win a second presidential term. “Under this administration, authoritarianism has taken root in our country. I, and my family, and many of yours, know the insidious way authoritarianism destroys democracy, decency and humanity,” Sanders said Monday.  Motivation to supporters Trump has repeatedly asserted that liberal Democrats like Sanders are out to “destroy the country,” and are promoting socialist values anathema to many Americans.  Sanders’ rhetoric was intended to motivate his supporters to vote for Biden instead of staying home or choosing another candidate.  FILE – Republican presidential candidate Donald Trump stands with Democratic presidential candidate Hillary Clinton before the first presidential debate at Hofstra University, September 26, 2016, in Hempstead, N.Y.“In 2016, as we all know, Hillary lost by about 68,000 votes in three key states, collectively, Pennsylvania, Wisconsin and Michigan. And in those states, 100-200,000 people voted for third- and fourth-party candidates and many of them didn’t vote at all. And that’s the key here. He [Sanders] has to motivate his supporters to get out and vote for Biden, not to vote for another candidate,” Thurber said. While noting that he still has significant policy disagreements with Biden, Sanders also outlined in his speech the many areas where progressive causes could be advanced if Democrats retake the White House. Biden’s campaign worked with Sanders in the weeks leading up to the convention to ensure some of his progressive goals were included in the official platform of the Democratic Party.  Sanders said Biden supported progressive causes such as raising the minimum wage to $15 an hour, paid family leave and funding for universal schooling for 3- and 4-year-olds while making child care affordable for millions of families.  Sanders did note that his Medicare for All plan – a single, government-sponsored health insurance program for all Americans – did not make it into the party platform.  “While Joe and I disagree on the best path to get to universal coverage, he has a plan that will greatly expand health care and cut the cost of prescription drugs. Further, he will lower the eligibility age of Medicare from 65 to 60,” Sanders said.  Control of Senate With control of the Senate also at stake this election year, analysts say a key part of Sanders’ appeal to progressives was to remind them that putting a Democrat in the White House was the best way of ensuring their agenda becomes law.  “He was very good at explaining to his supporters that progressives have won. They are now the mainstream of the Democratic Party. Their issues are the ones that are a top concern,” Brown said.  If Democrats pick up the three to four seats needed for a majority in the Senate, Sanders is well-positioned to play a key role in leadership. One of his Democratic colleagues recognized his contribution Monday night after his speech.  Senator Chris Murphy of Connecticut tweeted, “The careful, purposeful steps Bernie Sanders has taken to bring the party together this spring and summer will be a huge part of the story we tell when Joe Biden wins.”