gop.jpgGREENVILLE, S.C. (AP) _ South Carolina Republicans will argue in federal court Thursday that the state's political primaries should be closed, ending years of allowing anyone to cast a ballot in state-funded contests from president to town hall.

Requiring people to register by party would be a major change in South Carolina's presidential politics. The first-in-the-South primary held here since 1980 has been open to all voters and required candidates to make appeals both to the party's most conservative Republicans and GOP-leaning independents.

The Greenville County Republican Party and South Carolina Republican Party filed their lawsuit in June against the State of South Carolina, which doesn't require voters to register by party.

They want U.S. District Judge Michelle Childs to decide the case in their favor with a summary judgment order. Meanwhile, the state's attorney general has asked Childs to dismiss the case, saying the GOP can't sue it over the primary.

The lawsuit has prompted a backlash from independent voters, the Columbia Tea Party and black legislators.

They argue the change would limit access to primaries and, with the GOP already dominating South Carolina political offices, voters won't have a say in deciding who serves them.

Meanwhile, they argue the shift could lead to bigger racial divide in the state with more white voters registering as Republicans and blacks as Democrats.

Harry Kresky, a lawyer representing in the case, said 32 states have open primary voting systems and South Carolina is one of about 20 that don't require voters to register by party.