LEBANON, Ohio -- Less than 48 hours after Republican Sen. George V. Voinovich announced he would not seek re-election in 2010, the race to replace him got its first official candidate.

Former U.S. Rep. Rob Portman of Cincinnati, who served President Bush in two key posts, announced his candidacy for the GOP nomination at the Golden Lamb restaurant. Ohio's oldest continuing business, it has been owned by Portman's family for more than 40 years.

Following Voinovich's announcement Monday, Portman, 53, became the first candidate to enter a race expected to cost $25 million or more, and he rolled out a long list of endorsements from some of Ohio's wealthiest and most generous GOP contributors.

"I don't know how much it will cost, but I know I will have the resources," Portman said, noting that Republicans lost seats in the last two congressional races "in part because the Democrats were more effective at not just getting a message out, but at raising money. That won't happen in my race."

Portman, who represented southwestern Ohio's 2 ^nd Congressional District for 12 years until 2005 when Bush named him U.S. trade representative, still had about $1.5 million left in his old House campaign fund as of October.

If elected, Portman would be the first senator from Cincinnati since Republican Robert Taft Jr. left office in 1975 after being defeated by Democrat Howard Metzenbaum.

Portman might not be alone in the GOP field: state Auditor Mary Taylor said this week that she, too, is mulling a Senate bid, and former U.S. Sen. Mike DeWine has not ruled it out. Democrats who might get into the race include Lt. Gov. Lee Fisher, Secretary of State Jennifer Brunner and U.S. Reps. Tim Ryan of Niles, Marcy Kaptur of Toledo and Zack Space of Dover.

Joined by his wife, Jane, two of their three children, and his father at the historic restaurant and inn, Portman told more than 50 supporters jammed into an upstairs sitting room that after nearly two years of practicing law in Cincinnati, duty was beckoning him back to public service.

"Our economy is in crisis, and Ohio has been hit especially hard," Portman said. "We need proven leadership with a track record of cutting through partisan politics in Washington to address the many challenges we face."

Portman said he will run on his record of fiscal conservatism and bipartisan cooperation, saying he proposed balancing the federal budget and fought pork-barrel spending while in Congress. As a co-owner of the Golden Lamb, he said, he is suited to help small businesses and middle-class Ohioans.

"I understand some of the pressures that businesses are facing right now as they try to create jobs and opportunity," Portman said. "I understand what middle-class families are going through in Ohio. We have got to put politics aside in Washington and solve these problems."

As trade representative, Portman was responsible for implementing and enforcing trade policy. In 2006, Bush appointed Portman as director of the Office of Management and Budget, another cabinet-level post. Democrats already have signaled that they will tie Portman to the economic policies of the unpopular president.

Portman said he gained valuable experience as trade representative and budget director that will help him better serve Ohioans, but that his tenure in Congress is a more important consideration for voters.

"Honestly, I think the more relevant record is what did I do in Congress? What kind of member was I? What I did was focus on results. It's time to put partisanship aside, stop the partisan gridlock, cut through it, and do what's right for the people of Ohio."