There are 18 days before South Dakota's primary election.
One of the biggest races will be on the Republican ballot where five candidates are all squaring off for one spot.
There's a possibility there could be a run-off election if the top candidate doesn't get enough votes.
South Dakota state law says in high-stakes elections such as US Senate, US House and the Governor's race, the top candidate needs to get at least 35 percent of the vote. If that doesn't happen there will be a second primary.
Former South Dakota Governor Mike Rounds is the candidate four other Republicans are gunning for in the US Senate primary in two weeks. But if Rounds wants to be the candidate in November, he has to garner at least a third of the vote in June.
"If we don't have a candidate who receives 35 percent of the vote then we would have a secondary election with just the top two vote getters from the primary," South Dakota Secretary of State Jason Gant said.
In the Republican primary this year, there are five candidates. If no one gets 35 percent, a runoff would be held on August 12. South Dakota Secretary of State Jason Gant can't remember a time when that's ever happened.
"A secondary election isn't unique across the country. It would definitely be unique here in South Dakota. It would be the first time in possibly forever that we've had this," Gant said.
Whether or not it will happen this year is something South Dakota Republicans will find out after the June primary. Gant says with five candidates in the race, it's possible and he's alerted election officials across the state.
"We always talk of the possibility of a runoff election and should it happen we will get everyone together and make sure everyone understands what to do and we'll go forward with having another election," Gant said.
The runoff would include the top two candidates, however if there is a tie for second place, state law says the candidates who tie would also be included in the runoff election.