Former Rep. John Shimkus. | Pete Marovich/Getty Images elections Illinois' John Shimkus won't seek reelection

Illinois Republican John Shimkus announced Friday he won't seek reelection to the House next year.

The 12-term congressman, who is a senior member of the Energy and Commerce Committee, told KMOX-AM in St. Louis that he would retire at the end of his term.


"It has been the honor of my lifetime to be asked by the people of Illinois to represent them in our nation’s capitol. Each day I have tried to do this as best as I possibly could, and my success lies squarely at the feet of my incredible staff in Illinois and Washington, D.C.," Shimkus said in a statement.

Illinois' 15th Congressional District is heavily Republican: President Donald Trump won 70 percent in the district in 2016. But Shimkus' decision to retire is another sign that Republicans see a difficult climb back to the majority in next year's elections.

His signature legislative achievement was the passage of an overhaul of the nation’s primary chemical safety law in 2016.

"I will leave the political field knowing that I have served honorably and, with the help of many, accomplished a lot for my constituents, our state, and our nation," Shimkus said.