DES MOINES — Pete Buttigieg’s presidential campaign scheduled a rally here on a recent Saturday night, setting up a choice for local Democrats: see the mayor of South Bend, Ind., or watch a nationally televised Iowa Hawkeyes football game.

More than 700 people turned out — and stood for hours in occasional drizzle and frigid temperatures to hear Buttigieg speak from a small stage on Roosevelt High School’s front lawn.

“A big football game and lousy weather, and he gets 700 people? Things like that just don’t happen,” said Matt Paul, a local Democratic strategist who ran Hillary Clinton’s 2016 Iowa campaign. “Something is clearly ­going on.”

What is going on is Buttigieg seizing an opening in the Democratic presidential field, pushing his way into the gap between liberal Sens. Elizabeth Warren (D-Mass.) and Bernie Sanders (I-Vt.) and the more moderate former vice president Joe Biden.

“The way we think this shapes up is, if you want the most ideological, far-out candidate possible, you’ve got your answer. You want the most Washington candidate possible, you’ve got your answer,” Buttigieg said Saturday from his campaign bus in Iowa. “Everybody else, I think, can come our way. I think that’s almost everybody.”

That positioning represents a significant shift from Buttigieg’s posture when he entered the race. Buttigieg made early headlines by portraying himself as the vanguard of generational change, a 37-year-old seeking to become the first openly gay president and talking up big liberal ideas, like abolishing the electoral college and restructuring the Supreme Court. While his campaign says he still supports those policies, he rarely mentions them on the campaign trail these days.

Since late summer, he’s cast himself as a Midwestern pragmatist who offers “real solutions, not more polarization,” a slogan that dings both the less-defined Biden approach and the plan-heavy Warren strategy. More recently, he’s sharpened his criticisms against the ascending Warren on Medicare-for-all, the single-payer health-care plan advocated by her and Sanders, running statewide ads arguing that the proposals would take away choice for Americans.

Iowa is critical to Buttigieg’s campaign. While he has moved up in polling in the first voting state, below Warren but competitive with Biden and Sanders, he has not yet seen as significant a shift in national polling. He remains far less known outside the early states than the race’s front-runners.

His campaign hopes that a strong showing in the caucuses in February could vault him into the top tier across a wider range of states, particularly those not dominated by the white and educated voters who now represent his strongest supporters.

Buttigieg is not the only candidate seeking the same positioning but so far is the most successful. Former Texas congressman Beto O’Rourke once was seen as a contender for the space between Warren and Biden; he departed the race on Friday. Sen. Kamala D. Harris (D-Calif.) also has competed there, but has yet to develop either polling momentum or the vast fundraising network that Buttigieg has assembled to finance his effort. Last week, she contracted her campaign and is now focused solely on Iowa, hoping for the same momentum he’s counting on.

Buttigieg has an advantage, however, having quickly put together one of the largest campaign operations on the ground, with more than 110 staffers and 21 offices, on par with Warren and Biden. He is spending heavily on television advertising in the state — financed by the more than $51 million he’s raised so far this year.

“We need to do well in Iowa,” he emphasized Saturday on his second Iowa bus tour, which stopped in several cities in northern Iowa, mostly in counties that went for Trump in 2016.

With the Feb. 3 caucuses less than 100 days away, Democrats unaffiliated with Buttigieg’s campaign say they have recently seen growing interest in the Indiana mayor as Iowans anxious to defeat President Trump consider the issue of electability. Among those taking another look: Voters who believe Warren is too liberal to win the general election but worry about the candidacy of Biden, whose campaign has been hamstrung by questions about his family’s ethics and his less-than-stellar fundraising.

“I’m hearing from a lot of people that they like what Elizabeth Warren is saying, but they worry she may turn off voters who are moderates and Republicans,” said Steve Drahozal, chairman of the Democratic Party in Dubuque County, a traditionally blue area in northeastern Iowa that narrowly flipped to Trump in 2016.

More than 800 people recently turned out to hear Buttigieg speak there along the Mississippi River, one of the largest rallies in the area so far this year. While Biden remains loved and respected, Drahozal said, Butti­gieg is viewed by some Democrats there as a “more palatable candidate” who could win over liberal voters without scaring moderates.

He has all but declared that himself in recent days.

“I’m not about being in the so-called right place ideologically, whatever that means. I’m about having answers that are going to make sense,” Buttigieg said Saturday. “I think [Biden] and I share some things for sure, but also what I’m offering is very different. What I’m offering is the idea that there’s no going back to normal, there’s no business as usual.”

As he attempts to elbow his way into the field’s top ranks, Buttigieg has occasionally gone overboard. In an interview with Showtime’s “The Circus,” Butti­gieg said he thought the primary was shaping up to be a “two-way” race between him and Warren. He quickly walked back those comments — “I don’t think that came out right,” he said — even as he has continued to train his attacks on the senator from Massachusetts.

When he entered the presidential race last spring, Butti­gieg was a barely known Midwestern mayor with a hard-to-pronounce last name whose most substantial national exposure had been during his failed 2017 bid to become chairman of the Democratic National Committee. He has sought since to draw implicit comparisons between the last Democrat with an unusual name, seeking to be the first black president, and himself, seeking history as the first gay one.

In place of Barack Obama’s “Change we can believe in,” Buttigieg has threaded the needle on the campaign trail, promoting policies he says are realistic while also casting them as “bold enough to solve the problems in front of us.” He asks voters to visualize what the end of a Trump presidency would look like — and just how difficult it will be to pass new legislation.

“I’m asking you to really think about what it’s going to be like that day,” Buttigieg told the crowd in Decorah. “We’re going to be even more divided than we are today. . . . Think about how exhausted from fighting that this country’s going to be.”

That, too, dovetails with his newer criticism of Warren as being too pugilistic. In television interviews and at the last debate, he attacked Warren for supporting a “my way or the highway” approach to health care. (He favors maintaining the private insurance market but allowing Americans to buy into Medicare if they wish.)

He initially criticized Warren for not having a plan to pay for Medicare-for-all. After she released a proposal last week, Buttigieg called the math “controversial.” More broadly, he has accused Warren of inviting “infinite partisan combat” with her proposals of sweeping structural change.

Warren’s allies are closely watching Buttigieg but hope that her funding proposal will effectively quiet his criticism that she hasn’t been straight­forward about how she’d pay for her plan.

“There’s very little fear that he’s going to win the nomination. But he seems very happy to do a ton of damage in the meantime,” said Adam Jentleson, who was a top aide to former Senate Democratic leader Harry M. Reid (Nev.) and is close to Warren’s campaign.

“There’s the difference between attacks from the left and attacks from the right. And attacks from the right validate Republican attacks that will come in the general election. So anytime you attack someone from the right in the Democratic primary, you’re giving fodder to Republicans in the general.”

In Iowa, where Buttigieg has campaigned as a nice-guy candidate unwilling to engage in intraparty squabbling, his sharper elbows have prompted mixed reactions. His back-and-forth with Warren and others thrilled supporters who had been anxious to see Buttigieg do something to stand out in the historically large field of candidates.

“What we saw was a much more passionate, expressive Pete than we’ve seen in the past,” said Terri Hale, a longtime Democratic Party activist from Des Moines who endorsed Buttigieg over the summer and who, along with her husband, has been privately encouraging the mayor to show more fire in his candidacy. “We agree with his positions, with his values, but we’ve argued that he needs to be more expressive . . . to show more personality.”

But other Democrats wondered whether that might turn off those who have gravitated toward Buttigieg because of his earlier, more positive message. In southeastern Iowa’s Wapello County, which flipped to Trump in 2016, Democratic chair Zach Simonsen said he was at a recent house party hosted by the Butti­gieg campaign at which people went around the room listing the biggest reason they were interested in the ­mayor.

Many praised Buttigieg’s ­focus on his faith, but most said they liked that he came across as a nice guy. “A lot of people said they admired how he stayed above the fray and the negativity in the first few debates,” Simon­sen said. He wondered how Buttigieg’s “more aggressive and negative” tone would ultimately play with people in his county.

Buttigieg and his campaign are sensitive to the idea that he’s gone on the attack — arguing that he’s accentuating policy differences in a way that’s “factual and respectful,” as an aide put it. But Grant Woodard, a Des Moines lawyer and former Democratic strategist, said it can be a tricky balance for a candidate, particularly in Iowa, where voters tend to be more sensitive about negativity. He recalled the 2004 caucuses, when John F. Kerry benefited from spats between two other candidates, former Vermont governor Howard Dean and Rep. Richard A. Gephardt of Missouri.

“It’s a different ballgame here through caucus as opposed to the general,” Woodard said. “You’ve got to be careful in terms of criticism and negative campaigning because it could blow up in your face. You can ask Howard Dean and Dick Gephardt about that.”