U.S. Sen. Chuck Hagel said Monday that he'll retire from the Senate and doesn't plan to seek any elected office in 2008.
Hagel said he thought it was time for him to leave the Senate after two terms.
"I said after I was elected in 1996 that 12 years in the Senate would probably be enough, and it is," Hagel said during an Omaha news conference.
Hagel's exit means one more seat the minority Republicans will be forced to defend, and both parties are expected to bring in heavy hitters to vie for the vacated spot.
That could include Democrat Bob Kerrey, former U.S. Senator and governor, and Republican Mike Johanns, U.S. agriculture secretary and also a former governor.
Potential candidates have said they'll talk about their plans after the Republican senator makes his decision official.
In March, many people had expected Hagel to announce he was running for president, but instead he delayed his announcement about his political future until Monday.
And earlier this summer, rumors flew about Hagel leaving the Republican Party to join New York Mayor Michael Bloomberg on an independent presidential ticket. But that talk diminished in July after Hagel said he had no plans to leave the GOP.
Next fall, 33 Senate seats will be on the ballot, and the minority Republicans hope to defend the 21 seats they hold now. Hagel's decision is the latest setback for the party.
Sen. John Warner of Virginia and Colorado Sen. Wayne Allard both intend to retire, and incumbents in New Hampshire, Oregon, Minnesota and Maine face particularly competitive races.
In addition, Alaska Sen. Ted Stevens faces a federal corruption investigation, and Idaho Sen. Larry Craig is expected to resign following his arrest in an airport men's room sex sting.