NATCHEZ — Mississippi’s partisan voters will decide Tuesday if they will oust an incumbent who has been seated in the U.S. Senate for decades.

The general election for the Senate seat is not until November, but Sen. Thad Cochran, R-Jackson, faces a primary challenge from state Sen. Chris McDaniel, R-Ellisville, that could knock him out of the running.

Cochran is the third most senior senator and the second most senior Republican in the Senate. He took office in the Senate December 1978, though he was a congressman prior to that.

His challenger, McDaniel, began as a dark horse candidate, but with the backing of Tea Party-groups ran a highly visible campaign and ultimately took more votes than Cochran in the first round of primary voting. McDaniel has served in the state legislature since 2008.

A third Republican candidate, Thomas Carey, managed to draw just enough votes in the June 3 primary election to keep either Cochran or McDaniel from taking a clear majority.

Also on the ballot Tuesday is the much less visible Democratic run-off for a candidate in the state’s third congressional district. The Democratic candidates in the run-off are Doug Magee and Dennis Quinn.

Approximately 20 percent of Adams County voters cast ballots in the first primary election, and Circuit Clerk Eddie Walker said based on the number of absentee voters he expects a similar turn out for this round.

“There is pretty good interest in this race, but unfortunately 20 percent is not a good turnout,” he said. “I would like 100 percent turnout.”

Secretary of State Delbert Hosemann’s office said in a news release this week that if an eligible voter did not participate in the June 3 primary election, the voter may vote in either the Democratic or Republican run-off.

If a voter cast a ballot in the Democratic Primary, he or she may only cast a ballot in the Democratic run-off, and likewise a voter who cast a ballot in the Republican primary may only cast a ballot in the Republican run-off.

Walker said voters need to remember to bring an acceptable form of photo ID to the polls as required by Mississippi’s new voter ID law, but those who do not can vote by affidavit ballot and return to the circuit clerk’s office within five business days with a photo ID and have their votes counted.

Acceptable forms of ID include:

-Driver’s license.

-Photo ID issued by a branch, department or agency of the State of Mississippi.

-U.S. Passport.

-Employee ID issued by the U.S. Government, State of Mississippi or local government entity.

-Firearms permit.

-Tribal photo ID card

-U.S. military photo ID card.

-Student photo ID card issued by an accredited Mississippi university, college or community college.

-Any other form of photo ID issued by a branch, department or agency of the U.S. government or any other state government, such as a driver’s license from another state. Out-of-state driver’s licenses and expired license no older than 10 years are acceptable.

Those who need a voter ID can get one at the circuit clerk’s office by presenting:

-Any expired but valid document issued by the U.S. government or any U.S. state that shows the voter’s name and photograph.

-A birth certificate or other document with the voter’s full name, date and place of birth.

– A Social Security, Medicare or Medicaid card.

-A Mississippi voter registration card.

-A government check, utility bill, bank statement or utility bill issued within the preceding six months.

-IRS form W-2, wages and tax statements issued within the current calendar year.