BANGOR – While Mainers may have until midnight to file their federal income taxes, candidates for the state’s open congressional seat didn’t wait until the last minute before making taxes a campaign issue.

“Taxation with representation hasn’t been so hot either,” said Maine Rep. Stavros Mendros, comparing what he considers the nation’s oppressive tax burden with the impetus for the historic Boston Tea Party protests.

Mendros, one of four GOP candidates vying for his party’s nomination to the 2nd District seat now held by U.S. Rep. John Baldacci, made the comments Monday at a sparsely attended rally outside the Margaret Chase Smith Federal Building in Bangor.

The rainy noontime rally was held in conjunction with Monday’s deadline for residents in most of the country to mail their tax returns. Because of the Patriot’s Day holiday, residents of Maine and Massachusetts have until midnight tonight to file.

At the event, attended mainly by Mendros’ staff, the candidate noted that he and fellow Republican Richard Campbell, a former state representative from Holden, have both signed a pledge not to raise taxes if elected.

GOP candidates Tim Woodcock, a former Bangor mayor, and Kevin Raye, a former aide to U.S. Sen. Olympia Snowe, have not signed the pledge, offered by Americans for Tax Reform, a Washington, D.C.-based group opposed to new taxes.

A former aide to then-U.S. Sen. William Cohen, Woodcock said Monday that he wouldn’t sign the pledge because he thought it unwise to tie lawmakers’ hands especially in light of escalating turmoil abroad.

“Were facing extraordinary times and the government has to deal with a whole series of very legitimate government functions,” Woodcock said. “The evidence would have to be compelling, but where it is compelling you have to act responsibly.”

Raye, too, said that while he didn’t have a problem with the group’s political philosophy, he “wasn’t wild about pledges.”

None of the Democratic candidates in Maine have signed the pledge, introduced in 1986, according to an Americans for Tax Reform spokesman.

Damon Ansell, ATR’s vice president of policy, said that in his eight years with the group, only one Republican has been elected to the House of Representatives without signing the pledge.

“It’s a demonstration that you’re on our side. It’s a demonstration of common sense,” said Ansell, wary of candidates who say they’ll hold the line on taxes but decline to take the pledge. “Too often, they say something and do the exact opposite.”

But none of Maine’s delegation, including Sens. Snowe and Susan Collins, has signed the pledge, in which candidates promise to “oppose any and all efforts to increase the marginal income tax rates for individuals and/or businesses,” and “oppose any reduction or elimination of deductions and credits, unless matched dollar for dollar by further reducing tax rates.”

Collins aide Felicia Knight said Maine’s junior senator was hesitant to sign blanket pledges, but has been supportive of tax cuts throughout her term.

“She tends to look at issues based on their merits,” said Knight, noting Collins’ role in proposing tax deductions for teachers who buy supplies for their classrooms. “As a rule, she’s been supportive of tax cuts.”

President Bush has signed the pledge as have 249 members of Congress, Ansell said.