For now, Team Sanders is projecting a sunny outlook. “This is a campaign to win,” campaign manager Jeff Weaver told reporters at a Wednesday press conference convened to discuss the results of Super Tuesday. To hear the campaign tell it, the senator’s Super Tuesday victories in states across the country—Colorado, Oklahoma, Vermont, Minnesota—prove broad appeal. The campaign argues that Sanders would be a formidable challenger to a Republican candidate in a general election, and that minority voters will side with Sanders as they learn more about him. Clinton is not inevitable, Sanders’s senior strategist Tad Devine stressed on Wednesday. “If Hillary Clinton does not consistently win in the weeks and months ahead, in big states and in small, questions will arise around her candidacy,” he warned.

Still, there are plenty of risks to a protracted primary battle. The mark Sanders leaves on presidential politics could hinge on how strong a fight he ultimately puts up, and the way he chooses to take on Clinton in the weeks to come. Over the course of his presidential bid, Sanders has risen from relative obscurity to the status of a national progressive icon. He has shown that it is possible to raise vast sums of money while rejecting super PACs, the much-reviled political-spending operations capable of taking in unlimited corporate donations. He has demonstrated that praising Democratic socialism isn’t automatically disqualifying in a presidential race. But his ability to set precedent and shape the way future insurgent progressive campaigns are run could come down to popular perception over how seriously he challenged Clinton for the nomination. If Sanders drops out after a crushing defeat, it would be easier for next-in-line presidential candidates to write him off as a not-so-serious challenger and unworthy of emulation.

Sanders certainly has the financial resources to stay in the race. The campaign’s remarkable ability to bring in small-dollar donations has been held up, by the campaign and political observers, as a measure of its success. Sanders’s fans continued to donate in droves even after he suffered defeat in the South Carolina primary and the Nevada caucuses. Supporters could be even more motivated to give if they believe Sanders is under attack. But donations are typically easier to extract when people think their money will make a difference. If the race appears to heavily favor Clinton as the primary drags on, Sanders’s small-dollar cash could start to dry up. That would not only hurt the campaign financially, but would also make Sanders look like a far less viable candidate. Party elites and elected officials might be more inclined to dismiss him as a result.

The way Sanders chooses to campaign in the coming weeks could also be an important determinant of how his impact on the race is ultimately judged. Last month, Sanders started to articulate a more forceful critique of Clinton, effectively painting her as a politician who can’t be trusted and promising he would continue to “contrast my record to Secretary Clinton’s” as the race progressed. It’s common for politicians to spell out what they believe are differences with their opponents. For Sanders, the strategy could fire up supporters. But Clinton allies have worked to paint allegations that she is untrustworthy as part of a partisan hatchet job. If Sanders appears to give voice to the same kind of criticism that Clinton’s GOP opponents have lobbed at her, that could hand an advantage to the Republican challenger if Clinton prevails and Sanders does not.