IOWA CITY, Iowa -- This didn’t look like your typical pre-caucus rally in Iowa.

For one thing, there was Bernie Sanders, standing shoulder to shoulder with Ezra Koenig from the indie rock band Vampire Weekend and grumbling out the lyrics to “This Land Is Your Land.”

And then there was the crowd 3,500 strong -- almost all of them college students who’d packed the University of Iowa Field House, with a few hundred more unable to get in.

During the remarks that preceded his brief turn from political eminence to actual rock stardom, Sanders played directly to his audience, as he uttered nary a word about foreign policy but had a lot to say about pot.

“Today in Iowa or Vermont, some kid is being picked up for possessing marijuana,” Sanders said to resounding boos from the crowd, right on cue. “Now I know that none of you know anything about marijuana.”

After he’d gotten the knowing laughter he was seeking, the Democratic presidential hopeful pivoted quickly to make his earnest point about disparities in arrest rates for personal drug use among blacks and whites, and why he was the candidate to fix the problem.

“Now I know that many of your friends say, ‘Wow, you went to a political meeting? That’s pretty lame,’” Sanders said, doing his best to mimic college kid parlance. “In so many respects, this election is so much more important for your generation than for my generation.”

With the exception of 2008 -- when heavy youth turnout propelled Barack Obama to victory -- only about 3 or 4 percent of eligible Iowans under age 29 have typically turned out on caucus night.

It’s an unimpressive number that has to be much higher than that if Sanders has any chance at pulling off the upset over Hillary Clinton on Monday, which was why his campaign had pulled out all of the stops in making this event a particularly memorable one.

The crowd, in turn, was loud and engaged throughout the two-hour program. But by the time the 74-year-old Vermont senator had started singing, many of them were heading for the exits.

Mark Kauzlarich / Reuters

Will Olson, a University of Iowa senior, was among those in the crowd who’d begun to file out just a bit early to enjoy a Saturday night on campus. In a brief interview with The Huffington Post, Olson said that he had indeed come out to see Bernie, not the band.

“I just like how he stands up for all different kinds of people and likes to promote change in the whole political system,” he said.

So as a strong Sanders supporter, he definitely planned to caucus on Monday, right?

“I was going to, but we have an intramural basketball game, so I can’t make it out,” Olson explained.

Olson did add that he was thinking about skipping the game, “so we’ll see,” but his ambivalence about showing up to caucus was perhaps indicative of a surprising finding from the closely watched Des Moines Register poll that was released a couple of hours before the rally.

Though Sanders has long been drawing the most impressive crowds in rallies around the country, it is Clinton’s supporters here, the poll showed, who are actually more enthusiastic about their candidate.

Alex Cole, a junior, said that he’d seen Democratic and Republican candidates speak in person and remained undecided about who would earn his support.

But he did plan to show up, which was more than he could say for many of his friends who didn’t know the first thing about how to caucus.

“I don’t think most people understand that you’re going to go out there, and you’ve got to go talk to people, and they’re going to try to persuade you to go one way or the other,” he said. “It’s not just a ballot.”

Max Komes, also a junior, said that he was “definitely” planning to participate and had already looked up online how to find his caucus site, which was “at some high school.”

“I’m all for Bernie Sanders, man,” he said. “I really love the movement. It’s not about Bernie Sanders. It’s about the people coming up and taking control.”

But many of his peers who’d attended the rally, Komes acknowledged, had come for the entertainment, rather than the revolution.

“I don’t think most college kids are really into politics, which is a shame,” he said.

Komes isn’t the only one who believes that to be the case, as Sanders himself acknowledged. And on that point, the candidate issued a challenge to everyone in the crowd, whether they’d come to see him or Vampire Weekend.

“Now, what the pundits say … they say, ‘Young people, well, they come out for rallies, but you know what? They’re not going to come out and participate in the caucus,’” Sanders said. “So how would you like to make the pundits look dumb on Election Night?”