WASHINGTON (CNN) -- Former House Speaker Dennis Hastert will resign his congressional seat rather than serve out the rest of his term, two GOP congressional sources told CNN.
Rep. Dennis Hastert, shown in June, was House speaker from January 1999 to November 2006.
The Illinois Republican said in August he would not seek re-election in the state's 14th District.
Both sources said Wednesday evening that Hastert would make an announcement "soon" but probably not on Thursday.
"I think he is just done with being a member of Congress," a GOP aide said of Hastert, who has just over a year remaining in his term.
Hastert, 65, is the longest-serving Republican speaker in history, holding the post from January 1999 to November 2006.
He stepped down as the top House Republican leader last November after Democrats won a majority in the midterm elections, ending 12 years of GOP control.
When he was elected speaker in 1999, Hastert, a former high school teacher and wrestling coach, was an unlikely candidate. Though he had been in the House 12 years he had virtually no national profile and did not hold a top leadership position.
However, Hastert managed to build a reputation as a formidable leader, and by 2003 his Republican colleagues waived term limits to allow him to continue as their speaker.
Twelve Republican representatives have announced they are not running for re-election next year, either because they are retiring or they are running for another office.
In addition to Hastert, another big-name Republican leaving is Rep. Deborah Pryce of Ohio, who said when she announced her retirement in August "there is no perfect time, no good time to leave a job you really love." E-mail to a friend
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