Robert Byrd, D-W.Va.

A Democratic challenger for Manchin did step forward Wednesday: Ken Hechler, a 95-year-old former congressman and secretary of state. The primary will be Aug. 28.

He said his candidacy will be a chance for voters to oppose a controversial strip mining method known as mountaintop removal that exposes coal seams through large-scale blasting. Manchin is a champion of the state’s coal industry, which considers the method highly efficient.

“It’s not to attract attention to myself. It’s not that I even expect to win,” said Hechler, in Jamestown, N.Y., this week for a series of lectures on his days as an Army combat historian in Europe during World War II. “I want to give an opportunity for those who want to vote against mountaintop removal.”

One possible Republican challenger, Morgantown industrialist and former GOP party chairman John Raese, plans to say Thursday if he will enter the race. He challenged Byrd in 2006 and lost badly.

Capito decided not to run even after lawmakers passed a special election measure that would have allowed her to seek both a sixth U.S. House term and Byrd’s seat in November.

The 56-year-old Capito, who faces a political novice in the House race, said a dual candidacy would “create more uncertainty, invite a legal challenge, and misrepresent my priorities as a public servant. “

Capito also said she would not run for governor if Manchin were to win in November and trigger a special election for his job.

McKinney said Capito had been backed into a corner because of the potential downsides to seeking both offices, but he also said her decision was a letdown after the Legislature’s minority Republicans won the amendment allowing her to do so.

“They went out on a limb and really extended themselves to get that provision in there,” McKinney said. “They’re going to be disappointed, and I think most West Virginians will be disappointed.”

Political analysts said Manchin is heavily favored, and had given him the edge even in a matchup with Capito.

“He would be awfully hard to beat,” said Marybeth Beller, a Marshall University political science professor. “He’s very popular in this state, and is a social and fiscal conservative and so has broad appeal across party lines.”

Manchin, a 62-year-old centrist, first captured the governor’s office in 2004 after a term as secretary of state. He became chairman of the National Governors Association earlier this month, enjoys high approval ratings and was seen as a comforter-in-chief to victims’ families following April’s Upper Big Branch mine explosion, which killed 29 workers, and the 2006 Sago mine disaster.

The winner of the Nov. 2 special election will succeed Sen. Carte Goodwin, Manchin’s Democratic appointee to fill the Byrd vacancy temporarily. Goodwin, a 36-year-old lawyer and the governor’s former chief counsel, took office Tuesday.

After November, the Byrd seat will again go before voters in 2012. The 92-year-old Democrat, the longest-serving member of Congress in history, died June 28 with slightly more than 30 months left in his term.

The bid marks the latest rise in profile for the 62-year-old Manchin since the former state lawmaker captured the governor’s office in 2004 after a term as secretary of state. He became chairman of the National Governors Association earlier this month, enjoys high approval ratings in his state and was seen as a comforter-in-chief to victims’ families following April’s Upper Big Branch mine explosion and the 2006 Sago mine disaster.

West Virginia GOP Chairman Doug McKinney said he’s not heard from any Republicans seriously weighing a run. He noted that any candidate would likely need to raise several million dollars to mount a credible campaign in a short timeframe.

John Raese, a Morgantown industrialist and former Republican Party chair, has told reporters he was considering entering the race. He challenged Byrd in 2006, losing badly when history’s longest-serving member of Congress secured his record ninth Senate term with more than 64 percent of the vote. Raese did not immediately respond to a request for comment Wednesday.

Capito opted not to run despite a special election measure that would have allowed her to seek both a sixth U.S. House term and Byrd’s seat on the same Nov. 2 general election ballot.

The 2nd District Republican faces a political novice, Virginia Lynch Graf, as the Democratic nominee in her 18-county district.

The 56-year-old Capito said a dual candidacy would “create more uncertainty, invite a legal challenge, and misrepresent my priorities as a public servant. “

Capito also said she would not run for governor if Manchin were to win in November and trigger a special election for the resulting vacancy.

Capito said in a campaign statement that there has been enough chaos and controversy surrounding the vacancy in the U.S. Senate.

“The outcome could ultimately place my re-election to the House of Representatives in jeopardy and would leave the final decision in the hands of state officials rather than the voters,” she said.

The state GOP’s McKinney said Capito had been backed into a corner by the potential downsides to seeking both offices, But he also said her decision was a letdown after the Legislature’s minority Republicans won the amendment allowing her to do so.

“They went out on a limb and really extended themselves to get that provision in there,” McKinney said. “They’re going to be disappointed, and I think most West Virginians will be disappointed.”

Political analysts consider Manchin heavily favored to win, and had given him the edge even in a matchup with Capito.

“He would be awfully hard to beat,” said Marybeth Beller, a Marshall University political science professor. “He’s very popular in this state, and is a social and fiscal conservative and so has broad appeal across party lines.”

Beller also echoed Capito’s concerns about running for two office and noted that she is also considered a shoo-in for another House term.

The Nov. 2 winner would succeed Sen. Carte Goodwin, Manchin’s Democratic appointee to fill the Byrd vacancy temporarily. A 36-year-old lawyer and the governor’s former chief counsel, Goodwin took office Tuesday.

After November, the Byrd seat would again go before voters in 2012. The 92-year-old Democrat died June 28 with slightly more than 30 months left in his term.

(This version CORRECTS that Democrat’s Senate majority is not ‘slim.’ )