Rep. Tammy Duckworth of Hoffman Estates is set to announce a 2016 bid for U.S. Senate Monday, a source said, possibly setting the stage for a Democratic primary battle on the path toward a race with Republican U.S. Sen. Mark Kirk of Highland Park.
The Illinois Senate race next year is expected to be one of the country's biggest as Republicans seek to hold control of the chamber they pried from Democratic hands last year.
Duckworth could face a tough primary race against Democratic Reps. Bill Foster of Naperville, Robin Kelly of Matteson and Cheri Bustos of East Moline, among others.
If she advances, Duckworth vs. Kirk would be a campaign between two military veterans who have staged high-profile recoveries from physical challenges.
With both Foster and Duckworth floating their names for a race against Kirk, Republicans have already started putting the pressure on both months before Senate campaigns are official.
A Foster spokeswoman declined to comment, but he has said he's considering making the run.
Kirk won approval in the Senate this week for legislation he wrote to impose sanctions on Iran.
"While he looks forward to a vigorous campaign, the senator believes there will be plenty of time for politics, and he is focused on fighting for veterans who have not received the treatment and respect they have earned from our government, as well as advocating for policies that encourage economic growth and job creation," Kirk spokeswoman Alissa McCurley said in a statement.
Duckworth's Monday announcement will come eight days before mayoral election in Chicago and at a time when that contest is drawing a lot of Illinois' political attention.
Kirk is in his first term in the Senate after serving five terms in the House from the North suburban 10th District. Duckworth is in her sophomore term from the Northwest suburban 8th District.
Her departure from that seat would create a race from both sides to fill it in 2016 as seats without incumbents are often seen as prime opportunities for politicians who want to move up.
Talk show host and former U.S. Rep. Joe Walsh has said he's considering challenging Kirk in the Republican primary.