AUGUSTA – Promising optimism and emphasizing organization, former Maine House Speaker Patrick Colwell took over Sunday as chairman of the state Democratic Party after defeating two other candidates for the job.

Colwell, who will serve a two-year term, succeeds Dorothy Melanson of Falmouth.

Before turning over the gavel, Melanson said she had led the party through 2004 presidential caucuses in which a record number of Democrats participated, elections in which Maine delivered four electoral votes for unsuccessful Democratic candidate John Kerry, but in which Democrats recaptured majorities in Maine’s House and Senate.

“This has been an incredible term for me. This has been an honor,” said Melanson, who was also at the center of last year’s challenges to independent presidential candidate Ralph Nader’s clearance to appear on Maine ballots.

Melanson had said earlier that she was “not burned-out. I’m tired and ready to try something else.”

In Sunday’s balloting, Colwell defeated two other candidates who remained in contention for the job: Alison Smith of Portland, who organized for Howard Dean’s presidential campaign in Maine last year and formerly worked for the activist group Maine Citizen Leadership Fund; and Carl Pease of Hampden, vice chairman of the state party rules committee, who is also a Desert Storm veteran and has a master’s degree in public administration.

Marianne Stevens of Kingfield, who heads the party’s Franklin County committee, was elected vice chairwoman of the state committee without opposition.

Colwell, who traveled across the state to meet with local party leaders before his election, said his priorities include updating Democratic voting lists and harnessing the energies of volunteers who became active during the latest election cycle.

Colwell, who represented a Gardiner-area district before completing his maximum four consecutive House terms, said he was propelled to seek his new post by optimism about the party’s future.

“When you do this work, you’ve got to be an optimist,” he said.

Ticking off a list of legislative accomplishments for which he said Democrats deserve credit, Colwell said, “We’re the optimists and we’re right … We must take the Republicans on head-on.”

Challenges ahead include re-electing Gov. John Baldacci and Democratic U.S. Reps. Tom Allen and Michael Michaud in 2006, said Colwell, who drew cheers when he added, “and we have to elect a [Democratic] U.S. senator.”

Incumbent Republican Sen. Olympia Snowe has declared her intention to seek a third term next year.

Colwell had been encouraged by Baldacci to run for the party chairmanship.

As of last year, nonparty or independent voters composed the largest bloc of voters in Maine, followed by Democrats, Republicans and Greens.