The best campaigns — or at least the ones with organizers who suffer from obsessive-compulsive disorder and the resources to indulge them — think of everything. And this year, thinking of everything means helping your candidate's supporters sort out their child care issues so they can make it to their precinct by 7 pm and vote. The Obama and Clinton campaigns are both offering on-site child care at select sites and encouraging people to bring their kids. On the Republican side, the process is shorter, so child care is less of an issue. Still, it could matter for Mike Huckabee, whose supporters include large numbers of parents who home-school their children.