OMAHA, Nebraska ― Sen. Bernie Sanders (I-Vt.) and Rep. Keith Ellison (D-Minn.) called on an arena full of Omaha Democrats to get behind the city’s mayoral candidate Heath Mello on Thursday night, passionately appealing for unity hours after national reproductive rights advocates criticized the Democratic Party for backing an anti-choice lawmaker.

“Maybe, just maybe, it’s time to change one-party rule in Nebraska. And we can start right here, by electing Heath Mello as the next mayor,” Sanders declared to loud cheers.

Well before Sanders delivered his remarks, Mello had responded to the controversy by vowing that he would “never do anything to restrict access to reproductive health care” as mayor, notwithstanding his faith-rooted opposition to abortion ― and history of votes to limit abortion rights as a state lawmaker.

But Sanders and Ellison’s decision to stump for Mello well before that clarification underscored a disagreement within progressive ranks about where to draw ideological boundaries, with Sanders arguing that compromising on contentious social issues is the price of building political power outside the liberal coasts.

Ironically, enduring charges of progressive betrayal allowed Sanders to showcase his pragmatism and party loyalty on the fourth day of a cross-country “Come Together, Fight Back” tour with Democratic National Committee chair Tom Perez in which his own differences with the Democratic establishment have occasionally crept into the spotlight.

“We can all be pure. I would love it if everybody in America held my political views,” Sanders said after Thursday’s rally, in a locker room in the Baxter Arena that had been turned into a green room for the evening. “That would be great if 320 million Americans all agreed with Bernie Sanders on every issue. Unfortunately, that’s not the case.”

This is a progressive guy. We disagree on an issue. Sen. Bernie Sanders (I-Vt.), on Heath Mello

Sanders, who himself has faced accusations of excessive purism from Democratic critics, argued that supporting figures like Mello is an essential part of reviving the Democratic Party in GOP strongholds like Nebraska where Republicans control all congressional seats, the governorship, the legislature and the mayoralty of the largest city.

He likened his disagreement with Mello on abortion rights to divergences with other Democrats who supported the Iraq War, major international trade deals and financial industry deregulation.

“This is a progressive guy. We disagree on an issue,” Sanders said.

The Vermont senator’s team-player tone was a marked contrast with some of the scenes of intra-party dissonance that arose on earlier legs of his national tour with the DNC.

A handful of Sanders supporters booed at mentions of Perez’s name at rallies earlier this week in Portland, Maine, and Miami.

Then there were the divergent messages of Sanders and Perez themselves. In an MSNBC appearance with Perez on Tuesday evening, Sanders pointedly denied that he was a Democrat, telling host Chris Hayes, “I am an independent.”

Asked in the same interview whether he shared Sanders’ ire for the “ruling class of this country, the billionaire class,” Perez avoided the question, pivoting instead to talking points about Democrats winning when they “put hope on the ballot.”

Fort Worth Star-Telegram/Getty Images Sen. Bernie Sanders (I-Vt.) speaks at a Democratic Party rally in Grand Prairie, Texas, on Thursday. In the evening he spoke to a larger crowd in Omaha, Nebraska.

Earlier that day, Sanders declared that Georgia Democratic congressional candidate Jon Ossoff is “not a progressive,” according to a report in the Washington Post.

But by Thursday night, with political writers wondering whether Democrats would ever resolve their “existential crisis,” Sanders was walking back his characterization of Ossoff.

“I don’t know a whole lot about Jon. I certainly hope that he wins,” Sanders told HuffPost. “It would be an asset. It would be part of the process of reclaiming the House of Representatives for the Democrats.”

Sanders also offered more details about his reasons for not formally identifying as a Democrat. For practical purposes, he has caucused with Democrats since taking office in the House in 1991, and is now a member of the leadership of the Senate Democratic Caucus, Sanders noted.

What’s more, given the plurality of Americans who identify with neither of the two major parties, someone like him can help Democrats recruit independents, Sanders argued.

“The Democratic Party is going to have to work very very hard to bring those independents into the party, to make the case that the Democratic Party can represent their needs. So having an active independent in the Democratic Senate leadership, I think, is very positive,” he concluded.

A key to understanding the kumbaya atmosphere in Omaha is Sanders’ close relationship with Nebraska Democratic Party chairwoman Jane Kleeb.

Kleeb backed Sanders in the March 2016 Nebraska caucus, which Sanders won, and a few months later was elected chair of the state Democratic Party on the strength of the Sanders wave. She now sits on the board of Our Revolution, the successor organization to Sanders’ presidential campaign.

But Kleeb’s considerable accomplishments as a party chair and grassroots organizer in the state were clearly what impressed Sanders most. He implied that not traveling to Omaha to speak on behalf of Mello would have been an insult to her hard work and success in a state that Donald Trump won by 25 percentage points.

“She is great. She is exactly the kind of energy that we need for the Democratic Party,” Sanders said.

Daniel Marans The crowd at a Democratic rally in Omaha, Nebraska, held signs with the outline of Bernie Sanders alongside that of Heath Mello.

As founder of the multistate environmental advocacy group Bold Alliance, Kleeb earned progressive accolades for forging a new coalition of traditional green activists, native American tribes, farmers and ranchers to oppose construction of the Keystone XL pipeline. The various stakeholders believe the pipeline would threaten vital water sources on its way through Nebraska and neighboring rural states.

The enthusiasm and diversity on display at Thursday’s three-hour rally suggests Kleeb has brought some of that creative organizing to her leadership of the state party. The boisterous crowd of 6,000 that arrived to hear Sanders and Mello was dotted with dozens of “Bernie-Mello” signs distributed by the state party. The placards featured the already famous outline of Sanders’ white hair and glasses alongside an outline of Mello’s black hair with black sunglasses.

For his part, Mello, who has a sunny disposition, combined a local pitch filled with promises to improve pothole-ridden roads and pursue a “unifying aspirational vision” for the city’s development with an appeal to concerns about the policies of President Trump.

“We need leadership that’s also willing to stand up against those in Washington, D.C., who want to trample on our values … values like inclusion and having a mayor who stands with immigrants, refugees” and the LGBTQ community, Mello said, prompting roars from the crowd.

Although Sanders was clearly the evening’s biggest draw, many in the crowd also expressed excitement at Mello’s candidacy and the prospect of a Democratic glimmer in an otherwise deep-red state.

Myra Jo Bates, 68, a retired marketing professor and volunteer for Mello’s campaign, said that while Mello’s opposition to abortion “bothers” her, “nobody’s perfect.”

“I’m excited because he’s different and he’s going to be the mayor of all of Omaha, not just West Omaha, which is what we have now,” Bates said, referring to an affluent part of the city.

The Democratic Party is a broad party. We are pro-life; we are pro-choice. Jane Kleeb, chairwoman, Nebraska Democratic Party

In fact, Mello’s position on abortion did not come up at all over the course of the rally. The closest any speaker came was a remark by Kleeb implying that the existence of opposing views on abortion is simply a facet of the Nebraska Democratic Party’s diversity.

“The Democratic Party is a broad party. We are pro-life; we are pro-choice,” she said, before listing other factions like labor unions and “people that work in corporate America.”

At a smaller rally in Grand Prairie, Texas, just outside Dallas, where Sanders spoke earlier in the day, some of the lingering internecine battles were slightly more visible.

A group of Sanders supporters briefly broke into a chant of “Berniecrats, Berniecrats” during remarks by Dallas County Democratic Party chair Carol Donovan.

Later someone interrupted a speech by Texas Democratic Party chair Gilberto Hinojosa to ask if he supported the Trans-Pacific Partnership, the now-defunct 12-nation trade agreement negotiated by former President Barack Obama that was deeply unpopular with the party’s progressive base.

“No, I didn’t. In fact, the Texas Democratic Party, at my request, passed a resolution unanimously opposing the TPP,” Hinojosa responded, drawing cheers from the crowd. “Thank you for reminding me of that.”

Sanders’ presence on the stump was also reassuring to some of the disaffected Democratic activists and independents who flocked to his candidacy.

One of them was Joseph Landemeyer, a bearded 52-year-old who came with his brother from Gainesville, Texas, an hour away, to see Sanders in person.

Landemeyer has never identified as a Democrat, but he voted for Obama twice and Sanders in the primary. When it came time for the general election last November, however, he opted for Green Party candidate Jill Stein. Hillary Clinton was “not of the people,” given her speeches to big banks and her other corporate ties, Landemeyer said.

Enlisting Sanders as a prominent spokesman is “a good sign for the Democratic Party. They can’t be old-school values. They have to be new school,” Landemeyer said.