Mayor Sam Adams this afternoon tweeted his support of a plan to fluoridate Portland's water—giving the formerly-quiet-but-now-very-loud political push the three Portland City Council votes it needs to become official.

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Adams' endorsement of fluoridation comes a day after Commissioner Nick Fish, despite being on vacation, came forward with his own. So much for questions about political support raised by pro-fluoride frontman Randy Leonard only a week ago when the Oregonian broke news that a diverse coalition of health advocates, working with top political consultant Mark Wiener, was planning to go public with the controversial idea.

The announcement by the mayor leaves Dan Saltzman, also on vacation, as the only commissioner not to give some kind of statement or signal about his intentions. While Amanda Fritz hasn't yet said whether she favors a council vote to fluoridate Portland's water, she has said she's support a referendum on the issue.

That may, of course, be what happens no matter how the council votes this fall. It wouldn't surprise anyone if fluoride opponents, like they did 30 years ago, answer by collecting signatures for a ballot measure that overturns the council's will.

Fritz—no matter what she decides—also could face some electoral fallout this fall in her tight-fought re-election runoff race against State Representative Mary Nolan. Nolan told me this morning she fully supports fluoridation and doesn't agree that the council should farm out the decision to voters.

"This is the kind of decision we expect city council members to make," Nolan says. "The facts are very clear on the public health issues, and on the science issues, and, what I've not heard, on issues of fairness and equity for all the residential water users" in neglected parts of the city like East Portland.

Granted, it's not Nolan's vote—since, if she won this fall, she wouldn't take office until January. But the conundrum facing Fritz presents a good political opportunity. If Fritz votes against fluoride, Nolan can say she's not honoring principles of equity. But, then, if Fritz votes for fluoride, she risks alienating some very motivated fluoride foes. They won't vote for Nolan, so they might just sit out the race altogether.

Whenever fluoride comes up for a vote, it's going to be a long, long hearing.