Today’s announcement that failed Boston mayoral hopeful Sam Yoon will join an unofficial ticket with finalist Michael Flaherty injects a bit of excitement into what was shaping up to be a dreary slog to the November 3 election with an all-but-certain outcome. It certainly seems to have Mayor Menino’s campaign worked up into a lather, perhaps the surest sign that the move has at least introduced some uncertainty into a race that many said was over before it started.

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In a press conference this morning on City Hall Plaza, Flaherty announced that Yoon would serve as deputy mayor in a Flaherty administration. The move had been the subject of political chatter ever since the September 22 preliminary election, which saw Mayor Tom Menino and Flaherty place first and second, respectively, and advance to the final. Yoon finished out of the money in third, but only about 2,300 votes behind Flaherty, making his support — and that of his backers — almost an imperative for Flaherty if he is to stand any chance against Menino, who garnered just over half of the preliminary election vote.

The idea of an unofficial ticket for mayor is an unprecedented move in Boston politics, but that doesn’t necessarily make it a bad one. Menino partisans are sure to brand it a Hail Mary play by Flaherty, who finished more than 20,000 votes behind the mayor. But the move can also be spun as a reflection of the sort of bold, outside-the-box thinking that Flaherty and Yoon have both said is sorely lacking in city government and needed to move Boston forward.”Politics has been too much about getting credit and not about collaboration,” Yoon said this morning. 

There is no provision in the city charter for a deputy mayor. But if there’s one point that Menino’s opponents succeeded in driving home during the four-way preliminary, it is that Boston’s mayor enjoys enormous power to run city government as he or she sees fit. The position of deputy mayor existed under Kevin White’s administration, and nothing prevents Flaherty, if elected, from appointing Yoon to be the Number Two man in City Hall and handing him a broad portfolio of powers. Flaherty says Yoon, a fellow at-large city councilor, would oversee implementation of a 311 constituent-service phone system and help replace the Boston Redevelopment Authority with a city planning department. Flaherty and Yoon don’t see eye to eye on everything, but there are enough points of agreement to give their partnership some legitimacy on issues.

Yoon’s talk of a charter change to weaken the powers of the mayor’s office seems likely to go away, but Flaherty is now embracing his one-time rival’s call for mayoral term limits. That seemed all along like the more sensible stand to take in addressing the nearly unshakable hold on power that comes with the office. Term limits would leave Boston with a strong mayor system, so those elected to the office have lots of running room to carry out policies they campaign on. But it would also give a mayor a deadline for getting those things done and not allow him or her to maintain hold on power indefinitely for its own sake.

It’s unclear how much of a difference the Flaherty-Yoon team-up will make. Added together, their vote totals in the preliminary still fall short of Menino’s. And there is no reason to think that all of Yoon’s supporters will migrate to Flaherty, though it seems certain that more of them now will. The only real hope for Flaherty lies in a big bump in voter turnout in the final election, with those voters breaking strongly his way.  It remains a tall order, even with the boost he got today.

But the Flaherty-Yoon merger (already known as “Floon” in the blogosphere) seems nevertheless to have hit a raw nerve in the mayor’s camp. “This is a blatant attempt to confuse the voters of Boston, because implying that [Yoon is] going to run for deputy mayor is something that exists outside of the bounds of the law,’’ Menino campaign spokesman Nick Martin told the Globe. “These are desperate tactics by a desperate individual. This seems to be both councilors saying if they can’t win their way, they’ll try to reinvent the rules.’’

The tone of the reaction makes the mayor’s campaign suddenly seem like the one with a slight air of desperation surrounding it. Menino is the heavy front-runner, with an outsized warchest and a veritable army of city workers behind him. If the mayor is as confident about his record and standing with voters as he says, instead of getting so worked up about today’s development, his campaign ought to be saying he’s ready to take on two lame-duck city councilors with one arm behind his back.