MOORE’S SUMMARY: The foundation of Lt. Gov. Juliana Stratton’s larger-than-expected victory in the Democratic primary for U.S. Senate was laid with a dominant performance in Chicago but padded by a surprisingly strong showing downstate. She also kept up with Rep. Raja Krishnamoorthi in the Chicago suburbs.

WHY IT MATTERS: Stratton did well where she needed to, but in a state where regional differences are often pronounced, she managed to stitch together a fairly broad coalition that stretched the entire state.

Here’s a breakdown, featuring some neat interactive maps by my colleague Maggie Dougherty, of the results:

---

Open interactive chart in a new tab

---

COOK COUNTY: Chicago typically comprises about one-third of the state’s Democratic primary electorate; suburban Cook County about one-quarter. At nearly 60% combined, candidates need to at least be competitive here to win a statewide primary.

Stratton took 44% in the city to Robin Kelly’s 25% and Krishnamoorthi’s 23%. In the Cook County suburbs, Stratton won 36% to Krishnamoorthi’s 35% and Kelly’s 21%.

Stratton won nearly all majority Black precincts on the city’s South and West sides, nearly all majority Latino precincts on the Northwest and Southwest sides and most progressive white precincts on the city’s north lakefront and near Northwest Side.

In the Cook County suburbs, Stratton performed strongest in majority Black and Latino precincts west of the city as well as in the liberal bastions of Evanston and Oak Park.

---

Open interactive chart in a new tab

---

Krishnamoorthi, as expected, put up his best numbers in northwestern Cook County, the heart of his congressional district. In the city, his turf was largely restricted to the far Northwest Side near O’Hare and Southwest Side near Midway and Mount Greenwood. He also had a sliver of strength in the city’s Gold Coast neighborhood and suburban Cicero.

Kelly was strongest in Chicago’s south suburbs, which she represents in Congress.

COLLARS: As political coalitions realign, the five suburban collar counties are an increasingly important part of the state’s Democratic primary electorate. This year, they comprised nearly one-quarter of all voters.

Collectively, Krishnamoorthi won about 41% versus Stratton’s 39% and Kelly’s 13%, according to a Capitol News Illinois analysis. It was a far weaker performance than expected for the Schaumburg Democrat considering that his congressional district stretches into DuPage and Kane counties.

---

Open interactive chart in a new tab

---

DOWNSTATE: When Durbin leaves office, it’s likely there will be no statewide elected official who lives downstate. It’s a reflection of the region’s waning influence amid a conservative shift and shrinking voting power versus Chicago and the suburbs.

Still, the 96 counties outside Cook and the collars make up about one-fifth of the Democratic primary electorate. And in a result that surprised many political observers, Stratton won a plurality there, picking up 41% to Krishnamoorthi’s 37% and Kelly’s 11%, according to a Capitol News Illinois analysis.

Krishnamoorthi had been expected to post significant margins in the region given his sustained dominance on its television airwaves. But Stratton won in major population centers like the Metro East, Bloomington-Normal, Champaign-Urbana and Springfield.

Krishnamoorthi carried Peoria, the Quad Cities, Rockford and several rural counties in northwestern Illinois. He also did well in the rural areas of deep southern Illinois. Kelly won a plurality in Kankakee County, which is in her congressional district.

TAKEAWAY: Stratton delivered the strong performance she needed in Chicago but padded it with good numbers everywhere else. Krishnamoorthi won the suburbs, but barely. And the Peoria native lost downstate, a region he needed to post strong numbers in.

TL;DR: Stratton expanded upon her strong base in Chicago; Krishnamoorthi underperformed in the suburbs and downstate and failed to knock Stratton’s margins down in the city. Kelly could not broaden her support beyond her south suburban-based congressional district.