Seventeen Wisconsin State Senate seats are on the ballot Tuesday, Nov. 3, and the outcomes could end more than 15 years of Republican control of the chamber.

Republicans hold an 18-15 Senate majority. Democrats need to flip two seats without losing any of their own to take control, according to Wisconsin Public Radio.

"It'll boil down to a couple seats in the Milwaukee suburbs, probably," said John Johnson, a research fellow at Marquette University Law School.

The 2024 redistricting reshaped the Senate map. State senators serve staggered four-year terms, and this is the first cycle where all odd-numbered districts reflect the new boundaries. Democrats flipped four Senate seats in 2024 under the redrawn lines.

Racine-area seat is a top target

The open 21st Senate District, which includes Racine, Greenfield, Greendale and Franklin, is one of the races both parties are watching closely. Republican Sen. Van Wanggaard announced his retirement in March.

Democrat Trevor Jung, the transit director for the city of Racine, faces Republican businessman Jim Croft. Jung was elected as a Racine alder at age 23 and served two terms before becoming transit director in 2021. Croft, a first-time candidate, said helping business owners is a priority.

A Marquette University analysis found Democratic presidential candidate Kamala Harris carried the redrawn district by 1.3 percentage points in 2024, according to WPR.

Three other races to watch

District 5 is another open suburban seat. Republican Sen. Rob Hutton is retiring. State Rep. Robyn Vining, D-Wauwatosa, faces Republican Mike Roberts, a 39-year-old physical therapist who owns a business in Wauwatosa. A Marquette analysis found Harris carried the district by 6 points in 2024, according to WPR.

District 17 in southwestern Wisconsin pits incumbent Sen. Howard Marklein, R-Spring Green, against state Rep. Jenna Jacobson, D-Oregon. Marklein, a certified public accountant, won his 2022 race by more than 20 percentage points. But redistricting added parts of Dane and Crawford counties, shifting the district's lean. Data centers and a proposed transmission line have become central campaign issues. Both campaigns have raised about $1.5 million each, according to WPR.

District 31 in western Wisconsin is the only seat where Republicans see a plausible pickup. Incumbent Sen. Jeff Smith, D-Brunswick, won reelection in 2022 by about 700 votes. His challenger is Republican Eau Claire County Board Supervisor Michele Magadance Skinner of Altoona, who entered the race in April.

High turnout expected

The Wisconsin Elections Commission reported 796,607 absentee ballots returned before Election Day, including 465,291 cast through early in-person voting, according to WPR. That exceeds the early vote total from 2022.

Polls are open from 7 a.m. to 8 p.m. Voters must show a valid photo ID and can register at the polls with proof of residency, according to Wisconsin Watch.

How results are reported

Wisconsin does not have a statewide system for reporting unofficial results on election night, according to the Wisconsin Elections Commission's results page. County clerks post results for each polling place, and the Associated Press collects those numbers from the 72 county websites.

The AP will declare winners in state Senate races only when it determines no scenario would allow a trailing candidate to close the gap, according to ABC 7 Chicago. As of publication, the AP had not called any Wisconsin State Senate race.

Election-night totals are unofficial. Official results will be certified by the Wisconsin Elections Commission at a later date and posted to the commission's election results archive.