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Yesterday, along with Jason Cherkis, David Alpert finally made up his mind on the Mayor’s race. As with Jason, Alpert was genuinely conflicted over the decision, which may be why it took him so long to pull the trigger. When we talked about it before this profile came out, the problem was an overwhelming sense of uncertainty: Mayor Adrian Fenty has made mistakes, but he could change. And Vince Gray has made promises, but he could renege. Alpert thinks key staff like Gabe Klein and Harriet Tregoning are really important, and there’s no telling whom Gray might hire. But of course, the leading lights of the Fenty administration could always leave, or be marginalized.

In that kind of atmosphere, Alpert chose the path where advocates could at least have the most influence: A Gray administration. That takes a certain amount of confidence in your own influence, which Alpert rightly has—having taken care to record Gray’s public commitments, and now with a highly developed organizing tool in Greater Greater Washington, Alpert can raise hell if Gray backslides.

The other aspect to this is not about Gray, but about the marketing of smart growth itself. A cynical person might say that it’s an easier choice to endorse Gray now, while he looks poised for a win, and set yourself up to work well with an incoming mayor. Not being quite that cynical, I’ll just say that Alpert is very conscious of the smart growth’s vulnerability to charges of elitism, and it’s very important to ground this way of looking at public policy in a broad framework of social justice and advancement, as he does here:

Fenty and Gray both share a vision for a “world-class city,” which has good schools, a strong tax base including more residents and more jobs besides the government, more transportation choices besides driving, and a healthy and prosperous populace. Fenty is focused on getting us there as fast as possible, and if some people are left behind, well, a rising tide lifts all boats. Gray, meanwhile, will focus a little bit more on getting us there together. And getting there together is important to me.

So, while opting for Gray might not be the fastest or surest way of achieving smart-growth goals like an expanded streetcar or dense residential development, Alpert thinks it’s the choice that will put those priorities on the most sustainable path with the broadest support.

True to form, Alpert has also allowed dissent—if you’re set on Fenty, you can find a smart growthy rationale for that here.