Even as Florida attracts hundreds of new residents every day, the state’s pool of active voters is actually shrinking. This paradox is easily explained. All 67 counties must periodically scrub the voter roll to make it more accurate and to be sure voters live where they say. Counties can’t do that close to an election, so they do it in non-election years. Turns out, that’s good news for Republicans and bad news for Democrats. In Florida, a revolving-door state where people are constantly coming and going, the roster of active voters keeps changing. The voter roll expands in a presidential election year, when political parties are aggressively signing up voters, and it shrinks the following year, only to grow again, then shrink, like an accordion.