The two-term senator from the Cleveland area, a popular government official back home, opted not to seek a third term in November.
Voinovich's seat is considered vulnerable in the Buckeye State that once tilted strongly red but was more purple in 2008. In his march to the White House, Barack Obama won the state over Republican presidential nominee John McCain, 51 percent to 47 percent.
The candidate who will try to keep the seat in Republican hands is Rob Portman, former congressman, U.S. trade representative and director of the Office of Management and Budget.
Despite having been a congressman and a member of George W. Bush's administration, Portman portrays himself as a Washington outsider, Real Clear Politics reported.
"My concern is that Washington doesn't seem to get it," Portman said in an interview.
Portman once had a challenger, auto dealer Tom Ganley, who dropped out of the GOP U.S. Senate race to run against Democratic U.S. Rep. Betty Sutton in the 13th congressional district representing the Akron area.
On the Democratic side, Secretary of State Jennifer Brunner and Lt. Gov. Lee Fisher square off Tuesday.
Brunner is low on cash and endorsements but turned her lemons into lemonade.
"I ended up getting painted as an outsider -- thank God," she said.
Brunner is still slightly behind Fisher, a former state attorney general and state legislator, but some polls indicate 40 percent of Democrats were undecided, the Columbus Dispatch reported. Fisher suggested the numbers indicate voters have other things on their minds.
"Because so many people are trying to hold on to their jobs, or find a job, or put food on the table, this race is not a high priority," he said.
Fisher considers Brunner's challenge a serious bid, but still launches most of his salvos against Portman and his ties to Bush.
"I'm not somebody who's spent most of his life in the corridors of Washington, D.C.," Fisher told the Dispatch. "We're in the deepest economic ditch of most of our lifetimes, and two of the people holding the shovels were George Bush and Rob Portman."
Recent Rasmussen polling indicates Portman leads either Democratic candidate, but only by a few percentage points. His inability to forge ahead and the failure of either Democratic candidate to gain over the other indicates voters haven't begun to pay attention to the race and it's still wide open.
In the House, it will be the 2008 match between Democrat Steve Driehaus and Republican Steve Chabot -- only in reverse with Driehaus the incumbent and Chabot the challenger. Neither candidate has primary competition.
Another potential rematch is in Ohio's 15th congressional district between freshman Democratic incumbent Mary Jo Kilroy and Republican Steve Stivers -- if Stivers emerges from the primary as expected.
In the gubernatorial race Democratic incumbent Ted Strickland and likely Republican challenger John Kasich were in a virtual tie in mid-April, Rasmussen said. The poll indicated Kasich held a statistically insignificant lead of 46 percent to 45 percent, down from a month earlier when Kasich led Strickland by 11 percentage points, 49 percent to 38 percent.
Despite being elected by 60 percent of the vote in 2006, Strickland has watched his state's economy tumble and is feeling the effects of the anti-incumbent sentiment.
Ohio voters mirror sentiments about the recently enacted healthcare plan as seen in much of the country, but opposition seems to have little impact so far on the Senate race.
Forty-one percent of Ohio voters said they think the healthcare law is good for the country while 52 percent view its impact as bad, a Rasmussen survey indicated.
So far, Buckeyes favor kicking out congressional incumbents, Rasmussen found. Twenty-three percent of the state's voters said they thought the country would be better off if most incumbents were re-elected, but a whopping 58 percent said the nation would fare better if most incumbents were defeated.
A Rasmussen survey revealed 48 percent of Ohio voters said their views on the major topical issues align closer to the Tea Party movement activists than the average member of Congress.