US Sen. Thad Cochran reads over the ballot in a privacy booth prior to voting absentee in Oxford, Mississippi, Saturday, May 31, 2014.
The struggle for control of the Republican Party moved Tuesday to Mississippi, where the ultraconservative tea party movement has its best remaining chance to topple an establishment-backed candidate in a brutally fought Senate primary race.
Mississippi was one of eight states holding primaries that will help determine whether Republicans have a credible chance of gaining the six Senate seats required to take control of the chamber from Democrats in November elections. The Republicans are virtually certain to retain their House majority, and seizing control of the Senate would allow them to shut down President Barack Obama's liberal legislative agenda during the last two years of his term.
The Republican Party leadership has staged a concerted and mostly successful effort to fend off primary challenges from tea partiers they fear will be too right-wing for general elections voters in November.
But in southern Mississippi state, six-term Sen. Thad Cochran is facing the race of a lifetime against conservative challenger Chris McDaniel, who is carrying the hopes of anti-tax tea party supporters nationwide eager to topple a high-profile Republican incumbent after losses in Republican Senate primaries in Texas, North Carolina and Kentucky.
McDaniel has commanded considerable energy from Mississippi's conservatives to counter any damage his campaign suffered when four of his supporters were arrested on charges of photographing Cochran's bedridden wife in a bizarre plot.
Cochran's campaign seized on the arrests, airing a television commercial that said the four are McDaniel's backer, and saying, "Rise up and say, 'no' to dirty politics."
McDaniel has said his campaign knew nothing of the incident until after it occurred.
Cochran, 76, has campaigned with Southern gentility, the party establishment's support and a promise to leverage his Senate seniority for federal help for the state. He cast himself as a reliable opponent of Obama.
"Thad Cochran will never do anything to embarrass the state of Mississippi," said Rep. Gregg Harper, campaigning for Cochran.
An independent group that supports Cochran, Mississippi Conservatives, mailed a card to thousands of voters recently saying McDaniel would embarrass the state. The card played a few seconds of a talk radio audio recording of McDaniel from a decade ago, in which he said he had heard the word "mamacita" was a good pickup line for Mexican women.
In an interview between campaign stops, McDaniel said he wants to "end cronyism in Washington, D.C," and "repeal Obamacare in its entirety," referring to Obama's signature health care reform law. He said he would also push for a constitutional balanced budget amendment.
A 50 percent threshold is necessary to avoid a runoff in Mississippi's tough Senate Republican challenge, hardly a certainty in a race with a third candidate.
Mississippi elections officials said turnout was sparse in the first hours of voting.
The Mississippi race drew much of the attention among primaries across eight states. Nominations for the Senate are also on the ballot in Alabama; Iowa; Montana; New Jersey; New Mexico and South Dakota in a year in which Republicans need to gain six seats to win a majority.
Gubernatorial primaries are also taking place in five states.