The Senate will lose of one of its most influential moderate Republican voices next year, as Ohio Sen. George Voinovich said he will not seek another term.

Voinovich, 72, is a former Ohio governor and Cleveland mayor widely known on Capitol Hill as a practical politician, someone Democrats could work with. Most recently, he was an advocate of helping Detroit's Big Three with federal money, a position most of his GOP colleagues were reluctant to back.

"Those of us that have been given the honor to serve in these times must step up to the plate and put this country on a course that will see it through these harrowing times and make it strong and viable for the 21st century," he said. He was first elected to the Senate in 1998 and would have been favored to win a third term.

His departure is the fourth from Republican ranks in recent weeks. Also saying they would step down after the 2010 election are Florida's Mel Martinez, Kansas' Sam Brownback and Missouri's Christopher "Kit'' Bond.

Such departures are not unusual after a party has suffered the kind of big defeat Republicans endured last year. They have their lowest congressional numbers since the 1992 election.