BANGOR – Second Congressional District rivals Mike Michaud and Kevin Raye sparred last week over who had the tightest grip on the key to the politically sacred Social Security “lock box.”

Both Michaud, the Democratic nominee, and Raye, the Republican, have signed pledges – although slightly different pledges – to protect the retirement fund from those who would privatize or otherwise tamper with seniors’ benefits.

Flanked on Friday by about a dozen seniors donning “Raye for Congress” stickers at his Bangor office, the former chief of staff to U.S. Sen. Olympia Snowe signed a poster-sized pledge – a promise he said draws a distinct difference between himself and Michaud, the Maine Senate president pro tempore.

Raye pointed to a line in his pledge – absent in the Campaign for America’s Future pledge signed by Michaud last month – vowing opposition to any new taxes on the retirement fund, and blasted Michaud for his 1999 vote in the state Senate to tax higher-income Social Security recipients.

The 1999 bill, which spawned a deluge of calls to the governor’s office at the time, would have taxed anywhere from 50 percent to 85 percent of Social Security payments over $25,000.

Michaud aides said the legislation – which was promptly vetoed by Gov. Angus King – had the backing of the Taxation Committee and the AARP among other groups, and was designed to equalize state income taxes on Social Security and public pensions. Mainers, such as teachers and state workers, who receive public pensions are required to pay taxes on their benefits while Social Security recipients are not.

“It comes down to whether or not he voted to tax Social Security and senior citizens,” said Raye campaign manager Kathie Summers on Saturday. “It’s a matter of trust, and it seems unbelievable to me that someone would do that.”

Michaud press secretary Monica Castellanos scoffed at the idea that the blue-collar candidate would be anything but vigilant in protecting the retirement fund if elected to Congress.

“Shame on [Raye] for trying to scare seniors,” said Castellanos, noting that Michaud, a millworker at Great Northern Paper in Millinocket, will rely on Social Security when he retires. “He knows better than most the importance of Social Security to people in Maine.”

The issue, traditionally a Democratic one, could become important in the tight election, with seniors invariably citing it as among their top concerns in pre-election polls.

Recent polls suggest the issue is still high on seniors’ minds, especially amid the Bush administration’s recurring calls to explore privatization of some of the fund.

In a September survey conducted for a partnership comprising the Bangor Daily News, WLBZ 2 Bangor, WCSH 6 Portland and Maine Public Broadcasting, 32 percent of likely voters age 55 years and older cited Social Security as among their top concerns.

The same poll, conducted Sept. 7 to 10 by RKM Research and Communications, showed that Michaud – who has the endorsement of the Maine Council of Senior Citizens – fared better among older voters, 38 percent of whom supported him, compared to Raye’s 30 percent.

The poll has a margin of error of 5.7 percent.