Tea Party Republicans in Mississippi on Wednesday railed against an election rule that allowed Democrats, many of them black, to tilt a bitterly fought Republican U.S. Senate primary runoff to incumbent Thad Cochran.

But officials said the fuss was unlikely to lead to new electoral laws.

Tea Party-backed candidate Chris McDaniel, who declined to concede defeat in a fiery election-night speech, said on Wednesday he would decide within days whether to challenge the election results.

His supporters said allowing Democrats to vote in a Republican runoff undermined the integrity of the process.

“We just had the Democrats select the Republican candidate," said Barry Neyrey, a Tea Party activist from Long Beach. "That’s corruption.”

The Cochran campaign, which trumpeted the six-term incumbent's track record of steering billions of dollars in federal aid to the state, defended his courtship of black voters as an effort to expand the party's mostly white base.

Black voters turned out in large numbers in the Delta region and in greater Jackson.

"I think it’s a good thing when more people participate in the Republican Party," said Jordan Russell, Cochran's campaign spokesman. "We want to expand its appeal to more people, whatever background they may come from."

But the tactic also did not sit well with some of the 76-year-old incumbent's supporters, who said it smacked of dirty politics.

"I do not think that's proper," said Herlon Pierce, 75, a Hattiesburg bike trail manager and Cochran voter. "It's the law, but I wish the law was not the way it is."

Despite such protestations, a change in Mississippi's longstanding open primary law is unlikely, said state Representative Rita Martinson, a Republican serving on the state House's Apportionment and Elections Committee.

A number of other states have open primaries, including in presidential elections.

Republicans in heavily Democratic areas have in the past voted in Democratic primaries, she said, in a tradition that allows more voters to have a say in their elected leaders.

"There's no appetite for changing it on my committee," she said.

State Democratic Party Chairman Rickey Cole said he would prefer that voters stick to their own primaries, adding that the rift between Tea Party and establishment Republicans could help Cochran’s Democratic challenger, Travis Childers, in the November general election.

"These Chris McDaniel voters are fighting mad, and that’s not going to change anytime soon," he said.

[Image: American conservative tea party voters, fighting mad via Shutterstock]