Illinois will have its first new senator in a decade after voters in the 2026 midterm elections select someone to succeed retiring U.S. Sen. Dick Durbin, who has held the seat since 1997.

The election is expected to be hotly contested, with statewide officeholders and congressional leaders vying for the treasured post. The winner of the Democratic primary will likely have an advantage given how blue Illinois’ electorate is, but several Republicans also are weighing a run. Durbin’s retirement means U.S. Sen. Tammy Duckworth will become Illinois’ senior senator.

Here’s a look at the upcoming contest and how we got here.

Why is a Senate seat available?

Durbin, whose tenure as one of Illinois’ longest-serving U.S. senators has also been a testament to the power of seniority in the chamber, announced April 23 that he would not seek a sixth term next year. That has started a scramble among potential successors vying for a politically coveted six-year term.

“The decision of whether to run for reelection has not been easy. I truly love the job of being a United States senator. But in my heart, I know it’s time to pass the torch. So, I am announcing today that I will not be seeking reelection at the end of my term,” Durbin said in a video.

With Durbin’s announcement setting off a potential domino effect among Illinois Democratic members of Congress and others angling to run for his Senate seat, he did not endorse a potential successor. Instead, Durbin said the state was “fortunate to have a strong Democratic bench ready to serve. We need them now more than ever.”

Who are the major candidates to throw their hats in the ring?

Juliana Stratton, Democrat

Lt. Gov. Juliana Stratton wasted little time formally launching her bid for the Senate seat as she became the first major Democrat to enter a race that is expected to attract a large field of contenders.

Stratton announced her plans in a video posted on social media at 5 a.m. April 24, less than 24 hours after Durbin declared he would not run in 2026. The move was designed to position her as an early front-runner.

The decision by Stratton, a former state lawmaker, was not a surprise. The state’s lieutenant governor under Gov. JB Pritzker since 2019, Stratton announced in late January her interest in Durbin’s seat if he decided not to run, and she formed a federal political action committee. As she awaited Durbin’s decision, Stratton also increased her public visibility and moved forward on political hiring.

In her two-minute video, Stratton portrayed herself as an atypical politician who would take a different approach in challenging President Donald Trump in Washington.

“My story isn’t the story of a typical senator. Then again, typical isn’t what we need right now,” Stratton says in the video. “Donald Trump and Elon Musk are trying to distract us, to create such a mess that we don’t even know where to start. But in Washington, they’re still doing the same old things they’ve always done. And that old playbook isn’t working.”

Robin Kelly, Democrat

South suburban U.S. Rep. Kelly’s announcement on May 6 that she is vying for the Senate seat came about two weeks after Stratton launched her campaign with Pritzker’s backing.

The race for the party’s nomination to replace Durbin, who was an ally of Kelly’s, isn’t the first time the seven-term Democratic congresswoman from Matteson has faced off against a candidate backed by the billionaire governor and his political apparatus.

After working with Durbin in 2021 to defeat a Pritzker-backed candidate and become the first woman and first Black official to chair the Democratic Party of Illinois, Kelly dropped her bid to retain the seat a year later when allies of the governor rallied behind his handpicked state party leader, state Rep. Elizabeth “Lisa” Hernandez of Cicero.

“You could say I’ve been an underdog my whole life,” Kelly said in a 2½-minute video announcing her candidacy, referencing her upbringing helping out in her “family’s mom-and-pop grocery store” before putting herself through college at Bradley University in Peoria.

Raja Krishnamoorthi, Democrat

Five-term northwest suburban U.S. Rep. Raja Krishnamoorthi launched his bid May 7, pitching himself as the Democratic “radical commonsense progressive” to take on Trump.

“A president, ignoring the Constitution, out for revenge, acting like a dictator, claiming he’s a king, surrounded by billionaire backers and MAGA extremists, threatening our rights, rigging the rules to line their pockets,” Krishnamoorthi, 51, of Schaumburg says in his nearly 2½-minute video announcement. “Wrecking the economy, they profit and working people pay. It’s insanity. People want to know, at this moment in this time, where is the power to fight back?”

With his bid, Krishnamoorthi injects into the race a mix of moderate policy positions, such as supporting small business initiatives, along with progressivism as one of 19 vice chairs of the Congressional Equality Caucus, a group that promotes equality for all regardless of sexual orientation or gender identity.

Who else might be considering running?

Lauren Underwood, Democrat

A four-term Democrat from Naperville, Underwood had $1.1 million in cash on hand at the start of April, campaign records show. When Durbin announced he was not running for reelection, Underwood called him a “generous and thoughtful leader.”

Underwood represents a west suburban and exurban district that has supported her since she was first elected in 2018. But if she runs for Senate, that would mean the 14th Congressional District seat would be open, and Illinois Republicans would likely target it to steal from Democrats.

Alexi Giannoulias, Democrat

The first-term Secretary of State, who was also previously the state treasurer, ran for Senate in 2010 but lost in a heated battle to Republican Mark Kirk. While Giannoulias has experience running statewide and could be a legitimate contender if he runs for Senate, he is said to be eyeing a potential run for Chicago mayor.

Rahm Emanuel, Democrat

The former Chicago mayor, congressman, ambassador to Japan and chief of staff to President Barack Obama has been looking for a reentry into Democratic politics. But he prefers an executive rather than legislative post and is unlikely to seek Durbin’s seat, those close to him have said.

Darin LaHood, Republican

While the eventual Democratic nominee is expected to have the advantage in a state where party members have held all statewide elected offices since 2019, Republican U.S. Rep. Darin LaHood of Peoria has acknowledged he is considering a Senate bid.

LaHood, the son of former longtime GOP congressman and Obama transportation secretary Ray LaHood, had nearly $5.9 million in his federal campaign fund as of April 1. One of only three House Republicans in Illinois’ 17-member congressional delegation, LaHood has served since 2015 in Congress and has been a strong supporter of Trump.

Others who have filed paperwork with the Federal Election Commission stating their interest in running for the Senate seat were Democrats Christopher Alexander Swann, Stanley Leavell and Austin James Mink; Republicans John Goodman, Casimer Chlebek and Douglas Bennett; independent Anthony Smith and Joseph David Schilling.

Who is out?

Michael Frerichs, Democrat

The three-term Democratic state treasurer, Frerichs said May 5 he would not seek the 2026 Democratic nomination to succeed Durbin.

“There is a mess in Washington right now and we need to send someone who will fight for all of us in Illinois, but that person will not be me,” Frerichs wrote in an email to supporters. “I am not willing to travel to Washington, D.C., 30-some weeks a year and spend so many nights away from my children. I don’t want to miss their games, their recitals, or even that many bedtimes.”