EVERETT — A rivalry is brewing between the mayors of Edmonds and Mukilteo for a spot on the Sound Transit Board of Directors.

The conflict, bubbling with allegations of political payback and sharp words aimed at Snohomish County Executive Aaron Reardon, could come to a head Wednesday. That’s when the County Council is expected to take a decisive vote.

The seat in question is the one Mukilteo Mayor Joe Marine has represented for the past four years. He’s one of three Snohomish County leaders on the 18-member board governing Sound Transit. The regional transit agency oversees buses and commuter trains in Snohomish, King and Pierce counties.

Marine was hoping to be re-appointed after his term expired at the end of 2011. Snohomish County Executive Aaron Reardon has the authority to recommend who should serve on the Sound Transit board, but the decision is subject to County Council approval.

Reardon wants Edmonds Mayor Dave Earling. Marine said he has never heard Reardon complain about his performance on the board.

“It’s very clear to me that this is nothing more than political payback because I did not support Aaron Reardon in his re-election,” Marine said. “It makes me mad because I take my appointments to these regional boards very seriously, and that’s why I guess it makes me upset that he would replace me.”

Marine, like many others, is quick to acknowledge Earling’s competence. Earling has long been active in transportation issues, including a decade spent on the Sound Transit board.

Both mayors are Republicans who serve their respective cities in nonpartisan roles. During last year’s election, which saw Reardon win a third term in office, Marine had supported Reardon’s Republican opponent, state Rep. Mike Hope. Earling remained neutral.

In his recommendation letter, Reardon underscored Earling’s previous Sound Transit service while he was an Edmonds city councilman from 1992 until 2003. That included stints as the board’s chairman and vice chairman.

On Tuesday, Reardon praised Earling’s “unparalleled experience in both transit and growth-management issues.”

“Mayor Earling is simply the most qualified candidate for the post,” Reardon said. “My decision is based purely on the needs of our county and the qualifications of the candidates.”

Reardon added, “Joe’s complaint that my decision is political rings hollow: Mayor Earling is a known Republican and has never supported me in any of my races for county exec.”

When Reardon won his first term as executive in 2003, he beat Earling for the job.

Earling, for his part, said he was delighted when Reardon asked him to consider the appointment. He believes he has much to offer Sound Transit in terms of long-term experience and ideas for promoting transit-oriented development as light rail moves northward.

“I don’t see any political overtones,” he said. “It was his request of me because of the background and experience I have.”

Earling also hoped to draw on his experience serving on the state’s Growth Management Hearings Board. That’s the same governing body that ruled last year that Snohomish County failed to comply with state growth laws when it zoned the Point Wells industrial site next to Woodway for construction of more than 3,000 condos. The decision hinged largely on questions of traffic and transit access.

Only members of the Community Transit Board of Directors from south Snohomish County are eligible for this Sound Transit position. Marine is CT’s board chairman. Earling’s position on the CT board was confirmed early this year, following his election in November to a first term as Edmonds mayor.

Several members of CT’s board in February wrote a letter to the County Council endorsing Marine for the Sound Transit appointment. Mill Creek Mayor Mike Todd, vice chairman of the CT board, said Marine deserves the nod because of his recent experience with CT’s budget cuts. That includes eliminating Sunday bus service in 2010 and 100 positions this year, among them drivers, mechanics and administrative staff.

“These are both great people, they both have a deep background in transit,” Todd said. “Joe’s (experience) just happens to be a little fresher.”

The County Council is scheduled to vote on Earling’s nomination at its regular meeting at 9 a.m. Wednesday. The new term would expire at the end of 2015.

Noah Haglund: 425-339-3465, nhaglund@heraldnet.com.