With her Beltway profile rising, U.S. Sen. Susan Collins on Friday ended any remaining speculation over a rumored Blaine House run in 2006.

“I have decided that I am not going to run for governor next year,” Collins, R-Maine, said in a telephone interview while en route to a Washington airport. “My responsibilities are such right now that staying here allows me to best serve the people of Maine.”

Collins, chairwoman of the Senate committee on Homeland Security and Governmental Affairs, has gained notoriety in recent months for her work on creating the position of national intelligence director and leading an inquiry into federal relief efforts following Hurricane Katrina.

Collins’ definitive denial did not come as surprise in political circles, although she had been noncommittal about the prospect in previous interviews.

“I’m sure [Gov.] John Baldacci might be a little bit relieved today,” said Jim Melcher, a political scientist at the University of Maine at Farmington. “She would have been formidable, although not necessarily a shoo-in.”

As it stands, the GOP field against Democrat Baldacci includes two major hopefuls, the party’s 2002 nominee, Peter Cianchette of South Portland, and state Sen. Peter Mills of Cornville, both of whom Collins called “excellent candidates.”

Two other potential candidates, independent Nancy Oden of Jonesboro and Republican Stephen Stimpson of Bangor have also filed paperwork with state elections officials.

Baldacci spokesman Lee Umphrey on Friday said he took little stock in Collins’ early hedging on the question of whether she would run for governor. He called her decision to serve out her second term “good for Maine.”

“She’s done an exemplary job in Washington,” Umphrey said. “Hey, I’m going to vote for her.”

Earlier this year, U.S. Sen. Olympia Snowe, R-Maine, ended similar speculation about her Blaine House aspirations, announcing her intention to seek a third Senate term.