WASHINGTON — Representative Jim Sensenbrenner of Wisconsin, a Republican mainstay who found his way to the center of many of Washington’s most divisive political debates over the past four decades, said on Wednesday that he would not run for re-election next year.
“When I began my public service in 1968, I said I would know when it was time to step back,” Mr. Sensenbrenner, who has represented Milwaukee’s northern and western suburbs in Congress since 1979, said in a statement. “After careful consideration, I have determined at the completion of this term, my 21st term in Congress, it will be that time.”
The announcement adds to what appears to be a growing exodus of House Republicans this summer that promises to change the character of the chamber for years to come, regardless of whether the party wins back control next year. Sixteen lawmakers, including Mr. Sensenbrenner, have said they intend to retire or seek another office in 2020. Just hours earlier, Representative Bill Flores of Texas, said that he, too, would not seek re-election, citing a commitment to term limit himself. And more lawmakers are expected to follow suit.
[Bill Flores became the fifth Republican in Texas to bow out of the next election cycle.]
By contrast, Democrats have seen few retirements so far, though on Wednesday, Representative Susan A. Davis, 75, Democrat of California, said she would not seek re-election in her solidly blue district of San Diego.
Unlike the departures of some other Republicans, that of Mr. Sensenbrenner is unlikely to shift the political balance in the House. Republicans have carried his suburban and exurban district by comfortable margins in recent years, and political handicappers say there is little reason to believe his retirement would change that.
Still, few departing lawmakers have been as central to the party’s identity in the House as long as Mr. Sensenbrenner, 76, who cast more than 23,000 votes. A past chairman of two committees, including the influential Judiciary Committee, he played starring roles in the impeachment of President Bill Clinton, in the drafting and passage of the Patriot Act after the Sept. 11, 2001, attacks and in persistent immigration debates that have roiled Washington in the past decade or so.
An heir to the Kimberly-Clark fortune, Mr. Sensenbrenner famously won $250,000 in the D.C. lottery in the late-1990s.
He earned a reputation as equal parts conservative and cantankerous. His views on illegal immigration, among other issues, often irked Democrats, and as an impeachment manager, he helped prosecute the case against Mr. Clinton in the Senate’s trial of the president.
But Mr. Sensenbrenner also frequently teamed up with the opposing party on other major policy issues.
As Judiciary Committee chairman, he helped shepherd an extension of the Voting Rights Act. After the Sept. 11 attacks, he steered the bipartisan Patriot Act into law in 2001 to bolster the American national security apparatus in the fight against terrorism. And more than a decade later, after disclosures that the National Security Agency was using the law to collect phone metadata on millions of Americans without proper justification, Mr. Sensenbrenner helped lead a legislative fight to rein in certain provisions of the law.
Paul D. Ryan, the former House speaker from Wisconsin, said on Wednesday that he counted Mr. Sensenbrenner as a mentor.
“Jim has spent the last 50 years protecting our constitutional rights, ensuring the U.S. led the way in science and space and fighting tirelessly for conservative principles,” Mr. Ryan said.