COLUMBIA -- South Carolina Republicans said Thursday that they want to limit their primaries to registered supporters and are taking the issue to federal court.

The GOP says South Carolina's open primary system denies the party's First Amendment rights to free association.

The move comes as tea party activists challenge traditional political party structures. The chairman of the Columbia Tea Party called the closed primary idea revolting.

The state GOP and Greenville County Republican Party said Wednesday's federal lawsuit is aimed at forcing the Legislature to require voters to register by party before voting in primary elections. The litigation won't affect Tuesday's primaries.

"This is just the first step," said Greenville County GOP chairman Patrick Haddon.

Haddon said the party ultimately hopes the Legislature will force party registration as far in advance as 90 days.

"What we want is at least a 90-day period before the election where you can switch," Haddon said. But 90 days would fall well before the current candidate filing deadline of March 30.

Haddon said at a minimum, the party choice should be made 30 days before the election and that those are concerns and details that would have to be worked out by lawmakers.

It's unclear how the proposal would affect people who vote in Republican primaries but consider themselves political independents.

"Me personally, I think that's revolting," Columbia Tea Party Chairman Allen Olson said. "What they're doing is locking out a whole voting block." Olson said his group would discuss the issue, and he hoped people would get involved in challenging the litigation.

Haddon said there's no effort to cut people out of the party. "The last thing we want to do is push people off," Haddon said.