Super Tuesday's going to be rough for Bernie Sanders -- but his campaign isn't over

Bernie Sanders says he's in it to win it, as any candidate must, but he didn't enter this race in order to become the 45th president of the United States. In 2013, The Nation's John Nichols reported that Sanders “doubts that he would consider bidding for the nation’s top job if another prominent progressive was gearing up for a 2016 run that would provide a seriously-focused and seriously competitive populist alternative to politics as usual.” The following year, Sanders told Josh Eidelson, then with Salon, that he doesn't “wake up every morning with a huge desire to be president of the United States.” If he chose to run, it would be because “the nature of media is that presidential campaigns... are a means... of getting these issues out there.”

These are the words of a man whose goal is to advance the progressive movement and push the Democratic Party's center of gravity to the left, not someone who's in it to satiate his own hunger for power. In that sense, Sanders can't lose. He's already exceeded all reasonable expectations. Inequality, money and politics, the student loan debt crisis, our discriminatory criminal justice system, paid family leave and Wall Street predation have all been central issues in the Democratic debates. We've heard virtually nothing during this primary season about reducing the deficit, promoting overseas trade or reforming “entitlements.”

If Hillary Clinton goes on to secure the nomination and wins in November, Sanders' success shaping the debate will have far-reaching consequences. While there's a common view that politicians say what people want to hear in order to get elected, and then abandon their promises when they have a chance to govern, empirical research doesn't bear that out. Political scientist Jonathan Bernstein cited several studies which found that “presidents invariably attempt to carry out their promises; the main reason some pledges are not redeemed is congressional opposition, not presidential flip-flopping. Similarly... [a study of] party platforms... discovered that the promises parties made were consistent with their post-election agendas.” Sanders has pushed Clinton to lay down markers that progressives won't let her ignore if she wins the White House.

And he's done a lot more than set the terms of the debates. He's mounted a legitimate primary challenge from the left, showing that the party's progressive base can't be ignored. Sanders trails Hillary Clinton by just 6 percentage points in Huffington Post's average of the national polls at the time of this writing.

What he has failed to do is change the fundamental structure of the race. His shellacking in South Carolina wasn't significant because the state will be in play in November, or because Clinton walked away with 25 more pledged delegates than Sanders earned. It was important because it confirmed that Sanders' struggles winning African-American votes, whatever their causes, continue unabated, and because it left Clinton's status as the frontrunner intact.

Sanders hasn't enjoyed enough success to dislodge the common view among political reporters, elected officials, donors, party activists and groups affiliated with the Democrats (with a few exceptions) that he's a viable candidate, in the primaries and beyond. The idea that Sanders has “rattled the establishment” may make for catchy headlines, but it's simply not true. And that's something he had to accomplish in order to be truly competitive.

We may end up looking back at Iowa as the beginning of the end of his road to the nomination. While Sanders impressed many observers by fighting Clinton to a virtual tie, Nate Silver says that based on the state's demographics alone, he had the potential to take Iowa by 19 points. You can imagine how differently this race might have played out had he won the first two states decisively, and then come up five points short in Nevada. It not only would have created an entirely different media narrative, it may have panicked some of Clinton's establishment supporters into rethinking their assumptions about electability.

If the polls are right, Sanders' campaign is in for a rough day. They're now looking past today's big delegate haul to states with friendlier demographics. Sanders has campaigned hard in the Super Tuesday states, but he's also gone on to hold rallies in midwestern states that vote later this month – Kansas, Missouri, Ohio and Michigan. Sanders says he can still win, and that's not mathematically impossible. But unless those polls are wrong, it's going to be a tough road, one made even more challenging by the fact that in 14 states which hold primaries between March 5 and March 25, a half million college students – Sanders' strongest supporters – will be headed for spring break just as the campaign rolls into town, according to an analysis by Politico.

Calls for Sanders to step aside have begun, and we'll hear a lot more of them if Clinton ends up with a big delegate lead today and in the following few contests. But Sanders has no reason to go anywhere anytime soon. He may fall far behind in the delegate count, but he entered the quarter with $28 million in the bank, his fundraising remains strong and he's keeping the Democratic primary focused on the issues that are most important to the party's progressive wing. He can and should take his successful campaign all the way to the convention, and once there use his influence to help shape the Democratic platform.