The Illinois Senate Democratic primary will likely be one of the most competitive of the 2026 cycle, and could be expensive despite the state’s deep-blue hue.

Krishnamoorthi, who raked in $3 million in the first three months of the year and boasts a $19 million war chest, is “widely considered to be a contender” for the Senate seat, a source familiar with the matter told the Washington Examiner. 

He praised Durbin in a statement on Wednesday for his “legendary work ethic” and the “profound and lasting positive impact he’s had on Illinois families and our nation.”

“A champion for everyday families and an unyielding advocate for the underdog, Senator Durbin represents the true meaning of public service,” Krishnamoorthi, the top Democrat on the House Select Committee on China, said.

A source familiar with Kelly’s thinking told the Washington Examiner ahead of Durbin’s retirement that should he forgo reelection, she would “seriously consider running.”

“She’s keeping all options open and looking into it,” the source said of Kelly, the former chairwoman of the Illinois Democratic Party, when asked about forming an exploratory committee.

Underwood, who is a co-chair of the Democratic Policy and Communications Committee, is also speculated to be eyeing a bid. Ahead of Durbin’s announcement, she sent out a fundraising plea telling supporters she was “gearing up and getting ready” after a 314 Action poll found her statistically tied with Krishnamoorthi in a four-way race, 33% to 30% respectively.

The primary could put House Democratic leadership in a bind, particularly with three incumbents possibly battling against each other for the nomination. 

Other possible entrants into the race include Rahm Emanuel, the former mayor of Chicago. He has stoked speculation that he may run for president in 2028, but his name has been floated in Democratic circles as a statewide candidate. 

Lt. Gov. Juliana Stratton told state Democrats she’s interested in the seat and would have the financial support of Gov. JB Pritzker (D-IL) should he support her candidacy.

The seat was rated “solid Democrat” by the nonpartisan Cook Political Report when Durbin was still running. In a blue state that hasn’t elected a Republican senator since 2010, it is unlikely the seat will be a Republican pickup. 

However, Republicans still remain optimistic about the 2026 map, where the GOP is defending 22 seats to Democrats’ 13. Two Democratic seats, in Georgia and Michigan, are considered “toss ups.” Republicans have no toss-up races currently, though the seats of Sens. Susan Collins (R-ME) and Thom Tillis (R-NC) are considered competitive.

“4 Senate Dems already heading for the hills. 2026 is shaping up to be a great year for Senate GOP and they clearly feel that way too,” a GOP operative told the Washington Examiner.

DURBIN ANNOUNCES SENATE RETIREMENT, CLEARING WAY FOR LEADERSHIP SHAKE-UP

Senate Leadership Fund Executive Director Alex Latcham said in a statement that Senate Republicans are “delivering for the American people and will be rewarded next November.”

“Democrats see the writing on the wall: Retire now or face bloody primary battles where they’ll cave to their extreme base that demands unquestioned loyalty to MS-13 gang members and biological men in girls’ sports,” Latcham said.

Ross O’Keefe contributed to this report.