It doesn’t take much to start a political spat in Ohio, where jockeying for every presidential vote is practically blood sport. The latest pits President Barack Obama’s campaign against groups representing military voters, an uncomfortable place for the commander in chief. At issue is the legality of an Ohio law cutting three days out of the early-voting period for everyone except members of the armed forces and Ohio citizens living overseas. The dispute reaches court today, thanks to what the Obama campaign describes as its first lawsuit anywhere in the nation for the 2012 election. Put simply, looser rules for early voting are seen by both political parties as an advantage for Obama because they may encourage minorities, young people and other harder-to-reach voters to cast a ballot. Military votes are thought to lean Republican.