The preliminary election on Tuesday will send two messages — one about the mayoral candidates, and another about the Boston of 2013.
For the 12 would-be mayors, the vote’s verdict will be straightforward enough: Only the top two finishers will survive to meet in the final election on Nov. 5. The verdict on the city’s political makeup, though, may prove equally consequential. Simply by showing up, the electorate that turns out to vote Tuesday will provide a CT scan of what political Boston looks like now — and of the constituencies the next mayor will spend the next four years tending. Bostonians who want to maximize their voice in that future need to vote.