Tuesday’s results in Wisconsin’s Democratic primary may prolong a grudge match featuring Hillary Clinton’s math and Bernie Sanders’ momentum.

A tight race in the Upper Midwest and a long lull before the important New York primary on April 19 has sharpened the rhetoric between Clinton, who believes her party’s nomination is mathematically assured, and Sanders, who argues he can defeat the front-runner by pressing his case with voters and super delegates all the way to the July convention.

In Wisconsin, Sanders holds a 2.2.-point lead, according to the RealClearPolitics polling average, suggesting the neck-and-neck contest may come down to turnout and closing arguments. Both candidates have campaigned vigorously in the Badger State, while Sanders far outpaced Clinton in television ads (1,000 to 495) in the week ending March 28, according to an analysis by the Center for Public Integrity using Kantar Media/CMAG data.

On the heels of caucus conquests in Idaho, Utah, Alaska, Hawaii and Washington, Sanders has shown little patience for those who insist Clinton’s delegate lead is insurmountable. And having hauled in a record $44 million during March, largely from small-dollar donors, the Vermont senator believes he can barnstorm through the remaining states and broadcast his campaign appeals in major media markets for months to come.

“There are many, many states to go,” Sanders said last week while campaigning in New York, where he was born and Clinton served as senator (and where 247 delegates are in play).

“We are fighting hard in Wisconsin. We think we have a real shot to win in New York, and then it's on to many, many other states. We have won six out of the last seven caucuses. We have closed the gap in national polls,” he told ABC News. “We think we’ve got a real shot to win.”

Clinton disputes this. Her team argues that having carved out a significant delegate lead against her opponent and after capturing more primary votes, Clinton is destined to become the party’s standard-bearer. Sanders’ strategy of winning in states, especially caucuses, where he asserts momentum but does not close a gap with Clinton in pledged delegates is a formula for defeat, her campaign spokesmen insist. Roughly calculated, Clinton has to get a third of the remaining pledged delegates to win, while Sanders has to lasso two-thirds to get over the 2,383-delegate threshold. It would be a Herculean leap.

“The problem for [the Sanders campaign] … is they have a massive deficit in pledged delegates,” Joel Benenson, Clinton’s senior campaign strategist, told reporters last week. “I haven’t seen anything that … says they have been able to make a credible case that they have a path to winning this thing, because they don’t.”

That green-eyeshade delegate math may not be settled among the Democratic primary electorate until summer. Clinton’s campaign believes the facts will be crystal clear well before that, following the April 26 primaries in the Northeast, when 631 pledged delegates are at stake and could firmly lock the senator out of contention.

But for the moment, the optics of Sanders’ streak of victories, his boisterous fans and mass rallies, his blunt criticisms of Clinton’s wealthy donors and her record on issues, and his evident fundraising successes serve as reminders that voters in more than 20 states and territories have yet to cast ballots.

Asked her prediction about Wisconsin’s outcome, Clinton offered no boasts, except when it comes to her determination to leave nothing to chance, whether in Wisconsin, New York or the contests in May and June.

“We’ve got a really good organization and we're going to just keep working very hard to win every vote we can,” she said during an MSNBC interview. “I'm just committed to doing that. … So is Sen. Sanders' campaign. And, we'll see who turns out and votes on Tuesday.”

Age Gap

Where demographics and coalitions make a difference, Sanders has been able to count on the enthusiasm of younger supporters. Among likely Wisconsin primary voters who are 18-29 years old, Sanders is favored over Clinton by 83 percent to 12 percent. Among likely Wisconsin voters who are ages 30-44, the Democratic socialist leads the former secretary of state 59 percent to 37 percent, according to a Marquette University Law School poll conducted March 24-28.

The recent survey, which had a margin of error exceeding six percentage points, found that Sanders edged Clinton, 49-45 percent, among the state’s likely voters. A statistical tie as March ended, in other words.

The advantage Sanders enjoys among so-called millennials, a piece of his voting bloc on display since February, dissolves among older voters, who favor Clinton by margins of nearly 20 to 30 points, according to the Marquette poll. Clinton’s lead in Wisconsin over Sanders among women (two points) is not as pronounced as the senator’s advantage (14 points) among Wisconsin men who say they’re likely to vote in the Democratic primary.

Among the questions that dog Clinton this cycle is why the 74-year-old lawmaker from Vermont is such a Pied Piper among younger progressives, and what the former first lady can do to inspire Sanders’ youthful brigade to back her if she’s the nominee in November.

On the first question, analysts believe Sanders does well among younger voters because he channels worries about pocketbook issues they live with every day, as well as their urgent belief that systems are broken and need to be overhauled. The senator speaks their language. He validates young people’s concerns with storytelling they recognize – a narrative that seems genuine. His proposals are easy to describe. And he invites his supporters to join a reform movement, a cause.

“He has chosen to lead with several issues that poll particularly well with younger voters,” Betsy Hoover, a founding partner and digital strategist with 270 Strategies, said in an interview. Her firm, created by veterans of Barack Obama’s 2008 campaign, works with Clinton’s campaign. “It is definitely important to say that Sen. Sanders has an authenticity in his message and a set of issues that really resonate with younger voters. He has done a great job pulling in a key demographic,” she added.

Among the issues Sanders and Clinton are campaigning to fix are rising tuition costs and the burden of student debt.

“Millennials feel like they did everything right and they are getting the short end of the stick,” Colin Seeberger, strategic campaigns adviser for Young Invincibles, a research nonprofit focused on empowering young people, said in an interview. He cited double-digit youth unemployment nationwide, declining wages, and the generational impact on millennial parents who struggle economically.

“I would definitely say there is a sense of urgency that millennials feel. What we hear from young people is they can’t wait another four or eight years,” Seeberger said.

Citing his organization’s late-2015 polling about education, Seeberger noted that 61 percent of young respondents said a candidate’s solutions to the nation’s student debt problems would be a “major influencer” in determining their vote in November 2016.

On the stump and in her outreach to younger voters, Clinton has added a sense of urgency to her own proposals to improve college affordability and reduce student debt, while at the same time in Wisconsin she warned last week that Sanders’ pitch for tuition-free public higher education for all high school graduates would not be quickly achievable because of Republican opposition.

"His plan depends on governors like your governor, putting in a lot of money," Clinton said, referring to former GOP presidential candidate Gov. Scott Walker. "Now, I've got to tell you, having followed from afar the wrecking ball Scott Walker has used against higher education, I don't think it is all that realistic to say you will get free college as long as Scott Walker chips in about $300 million."

By criticizing Sanders’ college plan and touting her own “new college compact,” the front-runner in the Democratic race risks alienating Sanders’ young supporters, a group she would need in the fall against a GOP nominee. But her team believes Donald Trump or another GOP candidate would do more to inspire Democrats to unite behind Clinton than any single effort she might make to patch things up inside the Democratic Party.

Whether Trump’s campaign has shaped progressives’ votes during the nominating contest is unclear. As Trump has surged during the GOP primary contests, Sanders has maintained momentum against Clinton in caucus contests and two primaries, while besting the real estate mogul in poll questions that pit Sanders and Trump as potential rivals.

An expansive survey of the primary atmosphere conducted by the Pew Research Center, released March 31, found that Sanders’ supporters are underwhelmed at the thought of Clinton as a potential president. A plurality of 45 percent of Sanders’ backers said the former secretary of state would make an “average” president, while the same percentage of Clinton supporters thought Sanders would make a “good” or “great” president.

“Right now [millennials] are motivated positively by Sanders and negatively by Trump. In fact, the conversation is much more likely to start with Trump. He is a big factor in why this election matters,” Democracy Corps pollster Stan Greenberg said in an email Friday after releasing a new survey, conducted with Women’s Voices Women Vote Action Fund. The poll, which focused on Clinton more than Sanders, found that unmarried women back the former New York senator over Trump by a 52-point margin in a hypothetical match-up. That female demographic also includes millennials.

Greenberg said the resonance of “reform” – which could include changes to campaign finance, government operations, or higher education costs – “will be a big part of what unites” Clinton and Sanders supporters. “Clinton and millennials are very aligned on values, and that will become more and more evident in a race against Trump or [Sen. Ted] Cruz,” he added.

The Wisconsin Democratic results Tuesday may not settle questions about delegate math, momentum or millennials. But what’s a certainty is that Trump’s trajectory adds a little more intrigue and suspense.