Bernie Sanders has pulled off almost a complete turnaround in Wisconsin polls, taking what was once a double-digit deficit to Hillary Clinton and building it into a consistent lead just days before the critical vote.

After a string of victories in caucuses last week — including blowout margins in Washington, Alaska, and Hawaii — the Sanders campaign is looking to Tuesday’s Wisconsin primary as a chance to continue building momentum toward more difficult contests like New York. A win in Wisconsin is critical for Sanders, and polls point to a come-from-behind victory.

The polling aggregate site FiveThirtyEight now lists Bernie Sanders as the 70 percent favorite based on polls (though a more weighted forecast puts the race at roughly 50-50). A win in Wisconsin could help Sanders cut into Hillary Clinton’s large delegate lead, but more importantly could help turn the narrative in his favor and continue to build momentum among voters.

There could be other signs that Bernie Sanders is surging. Seth Abramson, an assistant professor of English at University of New Hampshire, wrote in the Huffington Post that Hillary Clinton is in the midst of a total collapse, with some of her key demographics turning to Bernie Sanders.

“There simply is no evidence available to suggest that Hillary Clinton’s robust coalition of nonwhite voters still exists — certainly not in anything like the form it was just four weeks ago. How else to explain an 82-point margin among nonwhite voters in Alabama, and similar margins in every other Southern state, on March 1st, and just a 6-point lead among all Southern Democrats (who are, depending upon the state, between 27 percent and 71 percent African-American) on March 26th?”

Amid his reversal in the polls, Bernie Sanders is also making the case that he is the best to represent the Democratic Party in November. Sanders appears to win the enthusiasm gap with voters, drawing larger crowds to events and out-fundraising Clinton over the past few months.

“We have received over six million individual campaign contributions averaging 27 dollars apiece — I believe that is the future of the Democratic Party,” Sanders said this week at a rally in Milwaukee (via ABC News).

In Wisconsin, Clinton says Sanders is a Democrat-come-lately @CNNPolitics https://t.co/vfEqFIS67w — Grace Laine (@TAW3343) April 3, 2016

Sanders has made the case that Hillary Clinton is too entwined with big interests, something he has stayed away from across his political career.

“I believe that we have got to tell Wall Street and the drug companies and the fossil fuel industry and all of the big money interests, ‘Sorry we are not on your side, we don’t want your money,’ ” Sanders said.

With Donald Trump on the horizon as the likely Republican nominee, Sanders has made the case that his party needs the enthusiasm he brings. Polls have consistently shown that Bernie Sanders outperforms Hillary Clinton in hypothetical matchups against Trump.

“We have got to do everything in our power to make sure that Donald Trump or some other Republican does not become president of the United States,” he said. “I happen to believe, based on all of the polling I have seen, and on other factors, that I am the strongest candidate to defeat Donald Trump.”

In order to have a chance at the Democratic nomination, Bernie Sanders will have to turn polls in other states the way he appears to have done in Wisconsin. Hillary Clinton has consistently held a double-digit lead in New York, where she served as Senator for eight years, though Sanders has cut the margin from roughly 30 points to the low teens. A win in Wisconsin could go a long way toward building momentum, but there is certainly still a very steep climb ahead for Sanders.

[Photo by Mark Wilson/Getty Images]