Vermont Sen. Bernie Sanders has almost no chance of winning the Democratic nomination, but he is likely to delight party activists as he takes unabashedly liberal stances and tries to push Hillary Clinton to adopt them.

The 73-year-old is officially not even a Democrat, but instead identifies as an independent and self-described socialist who has been in the Senate since 2007 and usually votes with Democrats. (Party rules allow Sanders to run for the Democratic nomination.) His political stances include support for a Medicare-like, government-run health insurance program for all Americans, increasing Social Security benefits and breaking up the nation’s largest banks -- policies neither President Barack Obama nor Clinton currently support.

Sanders, who announced his candidacy in an interview late Wednesday, holds many of the populist, anti-big business views of Massachusetts Sen. Elizabeth Warren, who has opted against running for president so far despite liberal activists begging her to run.

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“Are we prepared to take on the enormous economic and political power of the billionaire class, or do we continue to slide into economic and political oligarchy?” he asked in a December speech.

Sanders, though, is less well-suited to run a credible challenge to Clinton than Warren. Sanders does not play the part of the typical presidential candidate, both because of his age and his style, which leans toward long, dense policy speeches instead of the more aspirational rhetoric of Obama.

He is viewed by Democratic activists as a passionate foot soldier in their movement, not its potential leader. And key Democratic donors and elected officials prefer Clinton, both because they disagree with some of Sanders’ more liberal stances, like breaking up banks, and because they view him as too far to the left to win the general election.

Sanders has in some ways been rejected by the Democratic Party even before he officially announces his run. Howard Dean, the former Vermont governor who ran a 2004 presidential campaign that was embraced by many on the left, has already endorsed Clinton, like many other key figures in the party's establishment. Liberal activists have been ignoring Sanders, urging Warren to run even as Sanders spent much of the last year visiting early primaries states like Iowa and New Hampshire to raise attention around his potential candidacy.

Clinton is the overwhelming favorite to win the Democratic nomination. But if she were to falter or quit the race because of the controversies surrounding her foundation’s fundraising or her unusual use of e-mail as secretary of state, Democrats would still likely turn to other potential candidates, like former Maryland Gov. Martin O’Malley or Vice President Joe Biden, before Sanders.

His most important role in the 2016 process will be as a voice for the Democratic left, pushing Clinton towards more liberal policy positions. Party activists have largely conceded that Clinton will be the Democratic presidential nominee, but they want to use the next year to force her to take progressive stands including a minimum wage of $12 or higher and guaranteed debt-free four-year college for all American students.

Sanders is likely to advocate aggressively for these progressive policies in candidate forums and on stage at debates with Clinton. Democratic voters are very likely to support these ideas, putting Clinton in a position where she will have to consider them carefully . Her aides have already said she is examining the debt-free college proposal.

So Sanders almost certainly won't win the Democratic nomination or the presidency. But his ideas could win, if they are adopted by the ultimate standard-bearer for the party.