Instead of going to Boston, Stumbo said he would campaign for Dorsey Ridley (search), a former Kentucky House colleague who is the Democratic nominee in a special election for a vacant state Senate seat in western Kentucky.
Ridley's opponent is a recent Republican convert, David Thomason, who also served in the House with Stumbo.
Gov. Ernie Fletcher (search) called the special election for July 27, which coincides with the Democrats' convention in Boston, where delegates will formally nominate the John Kerry-John Edwards ticket.
The winner of the special election succeeds Paul Herron, a Democrat who died in June midway through his third term. Republicans hope to add to their advantage in the Senate, where they hold 22 of the 38 seats.
Thomason, an attorney and lobbyist who once was speaker pro tem of the House, changed parties last month after consulting with prominent Republicans including Fletcher and U.S. Sen. Mitch McConnell.
Stumbo said he had been looking forward to being a delegate. He said he changed his mind when Ridley asked him to campaign with him in the days before the election.
"We'll do the Kerry-Edwards ticket more good by winning that race down there than we would by being part of the crowd yelling for them in Boston," Stumbo said.
The district is made up of Henderson, Caldwell, Crittenden, Livingston, Union and Webster counties.
At one time, Stumbo and Thomason were roommates while serving in the House.
"I am surprised to hear that he is planning on spending so much time in the district based upon our long friendship, but I understand that he has further statewide aspirations," Thomason said of Stumbo.
State Democratic Chairman Bill Garmer said he wasn't aware of any other delegates planning to miss the convention because of the election.
"I think everybody is going to do everything they can before they leave" to boost Ridley's campaign, he said.
Stumbo said a Democratic victory in the special election would build momentum for the rest of the campaign.
Echoing other Democratic leaders, Stumbo accused Fletcher of putting the special election "on a fast track." The governor announced the election less than a week after Herron's death.
Stumbo said the governor deliberately timed the election to coincide with the Democratic convention.
"It's obvious that the Republican Party has manipulated that Senate seat," Stumbo said. "We're going to go down there and whip them."
Fletcher spokesman Doug Hogan responded that the governor's office received requests from people in the district for a quick election.
"We called the special election in a timely fashion," Hogan said. "And it's purely coincidental that it happens at the same time as the national convention."