Another House Democrat dipped his toe into the Senate waters Tuesday, one day after a former congressman said he is definitely in the race to succeed Sen. Paul Sarbanes (search) and a current congressman said he was out.

Democratic Rep. C.A. "Dutch" Ruppersberger (search), said Tuesday he would form an exploratory committee for the race and would spend the next few months traveling the state and listening to what people want from a senator.

Ruppersberger's quasi-announcement come a day after Kweisi Mfume (search) announced his candidacy and after Democratic Rep. Albert Wynn bowed out of the race.

Mfume, a former Baltimore congressman and former president of the National Association for the Advancement of Colored People (search), is the only candidate who was formally declared himself in the running, so far.

Ruppersberger, Wynn and three other House Democrats said Friday that they were considering a Senate bid: Reps. Chris Van Hollen (search), Benjamin Cardin (search) and Elijah Cummings (search). But none of the other three had announced a decision by Tuesday.

While speculation over potential candidates was rampant after Sarbanes' Friday announcement, some other high-profile Maryland Democrats have reiterated their decision not to run for the open seat.

Both Baltimore Mayor Martin O'Malley and Montgomery County Executive Doug Duncan, who are preparing for gubernatorial bids in 2006, said that they would not be entering the fray.

And Rep. Steny Hoyer (search), the House minority whip, said he will not run, his staff repeated Tuesday.

Ruppersberger, in his second term in Congress, dismissed questions about his lack of experience compared to the rest of the potential field.

"I'm not as worried about experience; I'm worried about what the issues are," he said.

Ruppersberger said he has a unique perspective because of his prosecutorial background and his work on the House Select Committee on Intelligence, and because he is the only one of the potential successors who has managed a major government. He was Baltimore County executive before being elected to Congress.

"It's a dangerous world," Ruppersberger said, "Unfortunately, terrorism, and the issues relating to terrorism are very relevant."

Ruppersberger said that his travels around the state will help introduce him to voters outside Baltimore County, but noted that he is "homegrown Maryland, all the way," with roots in the state and a degree from the University of Maryland.

Mark Plotkin, a political commentator for WTOP radio in Washington, said Ruppersberger's lack of statewide appeal may hurt him.

"I just don't see his support broad enough," Plotkin said. "He's unknown in Prince George's and Montgomery. His only constituency is Baltimore County."

Blair Lee, a political columnist for the Gazette newspapers, said the Democratic primary is currently a political "game of chicken," with each candidate waiting for the others to drop out of the race.

Lee said that Wynn's decision to drop out is "more important than Mfume getting in." The two Democrats, who are both black, might split the African-American vote if both stayed in, he said.

Both Plotkin and Lee said that Cummings' presence in the campaign represented a threat to Mfume's chances, but both also doubted that Cummings would stay in the race against Mfume. Cummings office said Tuesday he was still considering a bid.

If nothing else, Lee said, "in 2006, voters cannot say they do not have a choice."

Capital News Service contributed to this report.