Columbus, Ohio (AP) - Sen. George Voinovich said Monday he won't seek re-election in 2010, becoming the fourth Republican to make departure plans since the Democratic landslide in November.
The 72-year-old, considered a political moderate, said in a statement that challenges facing Ohio and the country will require him to devote all his energy to serving out his current term. Campaigning and fundraising would take time away from his work as a senator, he said.
"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," Voinovich said.
Voinovich also said he wants to spend more time with his wife, children and grandchildren.
The decision by Voinovich, considered a political moderate, set in motion jockeying in both parties to replace Ohio's senior senator.
Former U.S. Rep. Rob Portman of Cincinnati, who also served as budget director and trade representative under President George W. Bush, plans to run for the seat, a GOP official told The Associated Press.
Portman has already lined up fundraising guru Mercer Reynolds as finance chair, said the official, who requested anonymity so as not to pre-empt a forthcoming announcement from Portman.
Voinovich's announcement ends the political career of one of the most popular Republican politicians in recent Ohio history. Voinovich served as mayor of Cleveland and was a two-term governor before his election to the Senate in 1998, but recent polls have shown his support faltering and Democrats had viewed him as vulnerable in 2010.
In recent weeks, Republican Sens. Kit Bond of Missouri, Mel Martinez of Florida and Sam Brownback of Kansas have all announced plans to retire in 2010.
Voinovich's decision was more bad news for Republicans. Democrats, who are just shy of a filibuster-proof margin in the Senate, will be on the offensive in the races for four open seats.
Along with Portman, former Sen. Mike DeWine and former Ohio Secretary of State Ken Blackwell - who's currently in the running to become the GOP's national chairman - are believed to be possible Republican candidates. Lt. Gov. Lee Fisher and U.S. Reps. Tim Ryan and Zack Space are potential Democratic candidates.
Portman did not address his own plans in a statement praising Voinovich on Monday. "His countless contributions to our state and to our nation will be felt for many years to come," he said.
Ohio Republican Party Chairman Bob Bennett said Portman told him over the weekend that he was making calls and "feeling things out."
Voinovich was a strong supporter of a proposed federal bailout for the auto industry, which put him at odds with a significant portion of the GOP caucus. He released a strong statement following the measure's failure, saying the politics of his colleagues had "failed" the auto industry.
Associated Press Writer Sam Hananel in Washington contributed to this report.
Voinovich Retiring, Like 3 Other GOP Senators