Mike Segar / Reuters

Bernie Sanders’s beliefs have been obvious from the start. He thinks wealthy elites exert too much influence over American politics. He wants the U.S. government to lessen income inequality. He believes climate change is a pressing threat to the world. The clarity and overarching ambition of his agenda has been central to his appeal and expectations-defying political success so far.

If Sanders wants his political revolution to last, he will need to win widespread support for his ideas well into the future. Yet as the primary election draws to a close, the campaign has increasingly made arguments that may undercut the long-term viability of the movement that has coalesced around the Vermont senator.

The Sanders campaign has long made the case that the political system is beholden to the rich and powerful, and no longer adequately represents the interests of the people. That message animates supporters and has become a key rationale for the campaign. So it is perhaps not surprising that after Sanders supporters protested the Nevada Democratic convention earlier this month, the candidate decried party leaders. “Democratic leadership used its power to prevent a fair and transparent process from taking place,” Sanders declared. In the aftermath of the convention, Sanders’s campaign manager, Jeff Weaver, accused the Democratic National Committee chair Debbie Wasserman Schultz of “throwing shade on the Sanders campaign since the very beginning.”

In the short-term, accusing party elites of unfairly intervening in the political process might have a political payoff. It will likely motivate die-hard Sanders supporters to volunteer or donate money. And it could help Sanders gain leverage in the lead up to the Democratic National Convention. Fearful of the party being torn apart, party leaders may be more deferential to Sanders’s demands in the hope that he will ultimately help broker peace. There are already indications that the senator is starting to get his way. On Monday, The Washington Post reported that Sanders has been “given unprecedented say over the Democratic Party platform,” noting that party officials have permitted him to name five people to the “15-member committee that writes the platform.”

But in the long-term, the same strategy could undermine Sanders’s goal of creating a lasting political movement. If the campaign suggests the primary election has not proceeded fairly, its supporters may give up on the idea that political reform is even possible. The Boston College political science professor David Hopkins describes the risk this way: “Complaints about a rigged system may breed more apathy and cynicism than motivation to remain productively active in party politics,” he wrote in an analysis of the Nevada convention. “If the lesson drawn by Sanders and his supporters from the 2016 nomination race is ‘the fix is in’ rather than ‘good start—let’s get ’em next time,’ it will be harder to sustain momentum for their agenda within the Democratic Party and the electoral arena more broadly past the end of this campaign.”

Plus, the campaign could lose credibility if it makes claims that ultimately seem unfounded. Politifact awarded a “false” rating to allegations that the Nevada convention had been tainted by misconduct. And in the past week, the campaign appeared to undercut its own argument that it has not been treated fairly by the Democratic establishment. In December, Weaver told supporters the DNC had put “its thumb on the scales in support of Hillary Clinton’s campaign.” But during the CNN interview in which he accused Wasserman Schultz of “throwing shade,” Weaver suggested the problem was personal, not institutional. “It's not the DNC. By and large, people in the DNC have been very good to us. Debbie Wasserman Schultz really is the exception,” Weaver said. If the campaign sends mixed messages as it engages in the feud, that could divert the attention of supporters away from its big-picture ambition.  

The campaign has also opened itself up to criticism over its superdelegate strategy. Sanders called for “a serious discussion about the role of superdelegates,” a group of party elites and elected officials who can support either Democratic candidate, in a CNN interview this weekend. “The current situation is undemocratic,” he said. “It is ill-advised, and it needs to change.” But he seemed to hold out hope that superdelegates may still side with him, even if he does not win the most pledged delegates. The campaign has previously suggested it will fight for superdelegate support even if Sanders loses the popular vote, a strategy that has led to headlines like “Bernie Sanders’s Undemocratic Plan to Win the Primary.” Pronouncements that the campaign is willing to pursue an undemocratic strategy could hurt the candidate’s credibility with voters, whose loyalty he will need if he wants to make long-term progress on his policy ideals.     

After the Nevada convention, Sanders emphasized that the Democratic Party must decide whether it will “open its doors and welcome into the party people who are prepared to fight for real economic and social change”—in other words, his supporters. The Democratic establishment will have to consider what it can do to appeal to Sanders supporters. It appears that a concerted effort is, in fact, already underway. The Washington Post described the news that Sanders has been allowed to select five members of the platform-writing committee as “a move party leaders hope will soothe a bitter split with backers of the longshot challenger to Hillary Clinton.”

Whether Sanders supporters take refuge in the Democratic Party or outside of it will also depend on the way the senator navigates the election. Facing pressure to justify Sanders’s continued presence in the race, it’s not hard to see why the campaign might be tempted to pick every possible fight with establishment leaders. Highly publicized fights with party officials and disputes over the nitty-gritty details of primary election procedures, though, could leave less airtime for the senator’s policy agenda. Sanders may never again have the kind of platform he does now to preach his message of political revolution. To make the most of it, Sanders will need to use the time remaining to convince his devotees there’s a reason to invest energy in politics far into the future, or risk halting momentum for the movement he envisioned when he first got into the race.

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