Brandon Johnson’s election as Chicago’s next mayor represented a further leftward movement of the state’s Democratic-led politics, fueled by generational and ideological changes that are stretching and sometimes straining the fabric of the party’s big tent.

“In my view, the state of Illinois, led by Gov. (J.B.) Pritzker and this legislative body, has become the vanguard for progressive policy all over this country,” Johnson told lawmakers Wednesday to resounding applause while making his first visit to Springfield as mayor-elect. “You’ve done it.”

But Johnson’s 4% victory over Paul Vallas to become the city’s 57th mayor, laid bare some fundamental splits within the state’s Democratic Party that go deeper than just Chicago’s most recent mayoral contest.

Vallas billed himself as a “lifelong Democrat” despite ties to right-wing activists, the conservative Chicago Fraternal Order of Police, and his declaration in 2009 that he considered himself “more of a Republican than a Democrat” and was “fundamentally opposed to abortion.”

[ Mayoral candidate Paul Vallas insists he’s a lifelong Democrat. But he’s backed by conservative donors and the FOP. ]

In the end, Johnson succeeded in raising questions in voters’ minds about Vallas’ Democratic bona fides. Still, several older Democrats in the party establishment who are considered more moderate endorsed Vallas. They included former Secretary of State Jesse White and Dick Durbin, the No. 2 ranking Democrat in the U.S. Senate. Durbin served with Vallas in Springfield more than 40 years ago in the office of the late Democratic Senate President Philip J. Rock of Oak Park.

Christopher Mooney, a professor emeritus of political science at the University of Illinois at Chicago, said the Democratic leaders who backed Vallas look out of step with the way the party is headed.

“I think it’s not a good look for a lot of those folks,” Mooney said. “The progressives are in ascendancy in the state. You’ve got the governor and now the new mayor — two poles of political power in a state who are both proudly progressive.”

“The Democratic Party has always been a pretty broad base. Republicans … especially in Illinois today (are) very narrow. They have sort of an exclusionary interest — if you’re not for this, you’re out, or you’re a RINO (Republican in Name Only), you’re not a real Republican,” Mooney said. “Who knows if the progressives go that way too.”

The potential for increased friction between moderates and progressives threatening the party’s future has grown to the point that a special committee was formed by Cook County Democrats to determine what it means to be a Democrat in today’s political climate.

“What I started to see was there are Democrats that are confused,” said Northwest Side Ald. Gilbert Villegas, 36th, a member of the Cook County Democratic Central Committee, who is chairing the committee. “Your regular Democrats are confused as to what are the principles around being a Democrat, and how the Democratic Party is being influenced by some portions of the left.”

Villegas just won reelection to the City Council against a progressive challenger backed by the Chicago Teachers Union after last year losing a Democratic congressional primary to Delia Ramirez, a product of the progressive United Working Families organization whose candidacy was backed by U.S. Sen. Bernie Sanders of Vermont.

“My task was to figure out, the Democratic Party is a big tent. What are core pillars that we can identify with that would allow people who want to be a part of the Democratic Party to say, ‘You know what? Although I don’t agree with everything within the new Democratic Party, what are those core pillars that make me a Democrat?’ ” Villegas said.

[ In 36th Ward, two-term Ald. Gilbert Villegas declares victory over CTU leader ]

“So whether it’s making sure that we’re providing for working families, paying livable wages, a woman’s right to choose, affordable housing, what are some of the core things that, as Democrats, when a candidate from the Democratic Party speaks, is going to touch on those core pillars to say ‘Yeah, I’m a Democrat. But obviously I’m either more of a moderate Democrat or more of a left Democrat.’ So that way they get more of a sense of where they’re at within the big tent of the Democratic Party.” he said.

Pritzker, with the emergence of power of the legislature’s Black Caucus, has set out the template for the party’s progressive pillars — organized labor rights, abortion rights, LGBTQ rights, criminal justice reforms, including cashless bail for nonviolent crimes, and banning so-called assault weapons.

“The governor is leading by example. I mean, the guy is advocating very, very strongly and very, very emphatically, very, very nationally. Especially on abortion and guns. That’s right down Main Street for progressives,” Mooney said.

Pritzker acknowledged that Johnson represents “a new generation politician,” despite his age of 47, by bringing both younger voters and voters of color to the polls — important parts of what Pritzker calls “the Democratic coalition.”

The two-term governor said “older voters show up in large numbers and they’re very important” to party fortunes but “things are evolving” toward younger voters.

“The Democratic Party is much more resolute about the issues that we stand up and fight for,” Pritzker said. “That resoluteness certainly defines the younger generation and I admire that.”

One veteran Democratic campaign strategist, who asked not to be identified due to his links with current politicians, said generational change is morphing with a progressive ideology, in part due to greater educational opportunity — and social media and digital technology.

“The Black community, in particular, has a larger number of people who are college educated and moving into a gravitational pull of politics that makes them more progressive and more activist,” the strategist said. “Older voters, they’re not looking for revolutions. They’re just looking for things to be improved. They don’t believe the whole system needs to completely change over because when you’re older, you’re more of an incrementalist.”

As for moderate older Democrats, the strategist said, “The center never holds. It just adapts and that new generation takes over. They start paying taxes and try to change things and run into failures and then they get more incremental in the amount of change that they think the system can handle. Then the cycle repeats itself.”

In Springfield, members of the Democratic supermajorities have created a moderate caucus along with its progressive caucus — a recognition of the factional ideologies in the House and Senate.

[ Arguments over controversial no-bail law aired before Illinois Supreme Court ]

Those differences were readily apparent in the passage of the controversial Safety, Accountability, Fairness and Equity-Today Act, known as the SAFE-T Act, dealing with criminal justice and policing as well as cashless bail. Due to the overwhelming number of Democrats, some moderates representing a more conservative, less progressive ideology were able to vote against it without their votes needed for passage.

Moderate caucus leaders said it is paramount to represent the ideology of their districts, which brings geography in play. Democrats have seen their numbers reduced downstate, while increasing in the once traditional Republican suburbs and exurbs.

“They have their issues, we have our issues. You’ve got to work together and get a consensus,” state Rep. Marty Moylan of Des Plaines, a moderate House Democrat, said of his progressive colleagues.

“You know, sometimes their issues don’t agree with ours and then we’ll discuss it and try and come up with some kind of conclusion,” Moylan said. “(We’re) not going to agree on everything. But that doesn’t mean that we’re not Democrats.”

One major reason Democrats have not fractured so far is the political alternative — Republicans.

People, particularly in the suburbs, who might have once considered themselves moderate Republicans on social issues no longer fit into the narrow cast of what the GOP calls itself now, Mooney said.

And Pritzker said Republicans “have painted themselves into a terrible corner” on social issues.

“We are the party of reproductive rights. There’s nowhere else to go,” he said. “If you are a believer that women’s rights need to be protected, you are a Democrat and should vote for Democrats. If you’re a believer in public safety and protecting our children from being victims of mass shootings at schools, then you are a Democrat and should vote for Democrats.”

Chicago Tribune’s Jeremy Gorner contributed from Springfield.

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