Look at these results in the Louisiana 2nd Congressional district. It looks like there are nine Democrat candidates, three Republican candidates and one Libertarian. Have they never heard of primaries? And why is it undecided? The incumbent leads his nearest opponent by 8%.
What is going on down there?
Louisiana born and bred. Louisiana has run-off elections rather than primaries. That has advantages and disadvantages. The main advantage is that the two most popular candidates get to go to the runoff and it could be two people from the same party if that is the way it falls. Primaries force a contest based on party affiliations rather than people. The disadvantage of course is that you have to have two elections unless someone is extremely popular the first round and that just isn’t going to happen with so many candidates. The eventual winner has to hit over 50% and that is what the runoff sorts out.
Not in Louisiana.[sup]1[/sup]
Louisiana uses a run-off system. If no candidate achieves a majority, the top two finishers compete in a run-off next month. So it will come down to Democrats Jefferson and Carter.
[sup]1[/sup]They do have primaries for Presidential and (I think) Senate elections.
Interesting. Consider my ignorance fought.
What other states do this?
Louisiana is the only one AFAIK.
Louisiana is weird.
In many ways…
Louisiana is our only state to retain quite a bit of its Continental heritage. It also just likes to be different, at times. 
“In Louisiana, they have the Napoleonic Code.”
No other state does it regularly, although a few use this format when a special election is required. Louisiana began using it in 1975.
What do you expect from a state with no “counties” and drive-through daquiri shops?
San Francisco uses a ranked-choice ballot for several of its city offices; most offices this year had a clear winner, but my supervisory district has three close contenders, and they’ll have to go through at least three rounds of elimination to find a winner. Each round involves counting the second and third choices on the loser’s ballots.