By Tim Redmond

A new poll done by David Binder and Associates suggests that Mayor Ed Lee is popular, but not unbeatable – and the strongest challenger could be Assemblymember Tom Ammiano.

The poll, taken over the past two weeks, shows that both the mayor and the Assemblymember get high approval marks for job performance. Ammiano is over 50 percent, Lee closer to 60 – about nine points difference. Lee has slightly higher negatives than Ammiano, a source who has seen the poll told me.

The poll tested a number of possible mayoral candidates for a race that is still two years away – a lifetime in politics. It came right after high-profile events like Batkid put the mayor in a positive spotlight pretty much across the board, and at a time when Ammiano’s rate of success in Sacramento (this year the governor signed all 13 bills Ammiano sent to his desk, a remarkable record for a progressive from San Francisco) has gotten almost zero media attention.

Among the other potential challengers, City Attorney Dennis Herrera was in the 40s, with Sup. John Avalos, who came in second in 2011, further behind.

Ammiano, who will be termed out after 2014, has made no public statement about his plans. But he shows no signs of slowing down at age 72, and it’s likely he will seek some role in local politics in the future.

A mayoral campaign, of course, is a grueling effort, and would involve raising large amounts of money – never easy for someone who would be out of office at the time.

When I called Ammiano today to ask for a comment on the poll results, he told me “anything is possible.” But he’s a long way from even thinking about making any specific plans or announcement.

Still, while Randy Shaw thinks the mayor is the second coming of Bill DeBlasio, or God or something, there’s a pretty good chance someone with some substance will run against him in 2015. The anger in this city over housing issues is at a boiling point, and while Lee is now talking about the Ellis Act and making some changes, there’s no question that the tech tax breaks he pushed have helped create the problem he’s now trying to solve. And it’s not clear how much he can do in San Francisco to protect vulnerable populations. Herrera is already acting a little like someone who wants to run again. And Ammiano? Who knows. Anything’s possible.