Bernie Sanders continues to perplex pundits. Why is he still in the race, given that he’s sure to lose to Hillary Clinton and, some argue, should be helping the Democrats unite to defeat Donald Trump? Over the weekend, Edward Luce in the Financial Times suggested that Sanders is “the ghost of Ralph Nader”: a spoiler who will make an independent bid which will destroy the Democrats. Earlier, Josh Marshall in Talking Points Memo suggested that the “toxicity” of the Democratic primaries was driven by Sanders’s unwillingness to “let it go.” Both theories imply that Sanders is the type to let his vanity derail the Democrats and elect Trump.

But what if Sanders isn’t a Nader-type spoiler or a losing candidate in denial about the inevitable, and instead has his own theory as to how to defeat Trump? Sanders is staying in the race in part to gain greater leverage to push the party to the left, but this ideological motive is not disconnected from realizing that Trump is a menace.

Part of the difference between Clinton’s liberalism and Sanders’s leftism is their differing views on how best to defeat Trump. Clinton has already indicated that her strategy includes wooing moderate Republicans, including donors, who are disaffected because of Trump. This approach goes against Sanders entire raison d’être as a candidate: to prove that Democrats can win elections by running on progressive platforms and relying on small donors.

The Trump threat is being used as a cudgel to convince Sanders to give up his campaign. A series of new polls show that Clinton and Trump are virtually tied in a head-to-head matchup: According to an NBC/Wall Street Journal poll, Clinton has only a three-point advantage (46 percent to 43 percent), while a Washington Post/ABC News poll has Trump with a two-point lead (46 percent to 44).These numbers reflect the fact that Republicans have consolidated behind Trump while Democrats remain divided: Liberal independents, a key Sanders demographic, are hesitating to say they support Clinton against Trump. The New York Times’s Nate Cohn noted that “Bernie Sanders’s supporters are a big reason Clinton is doing worse in her polling against Trump. In the recent YouGov poll, Clinton had just a 40-point lead against Trump among Sanders voters, while Sanders had a 70-point lead. Trump was getting virtually the same share of the vote against both candidates—40 percent against Clinton, 39 percent against Sanders. Presumably most Sanders supporters will ultimately get behind Clinton.”

Sanders isn’t prepared to surrender just yet, but the hyperventilation of some Clinton supporters and the worry that he could spoil her chances are completely unfounded. In fact, close attention to his recent moves reveals that Sanders is carefully trying to thread the needle of acknowledging that Clinton is the nominee while also securing a greater voice for his progressive politics in the Democratic Party, particularly by making a push to reshape the Democratic National Committee and the party platform, which will be hammered out in Philadelphia.