BATON ROUGE, La. (AP) — Following a push by Louisiana Gov. Jeff Landry, lawmakers advanced a bill Wednesday that would overhaul the state’s unique open “jungle primary” system and move to a closed party primary.

Under Louisiana’s “jungle primary,” all candidates regardless of party face each other on the same ballot. If no one candidate tops 50% in the primary, the top two vote-getters advance to a head-to-head runoff, which can end up pitting two Republicans or two Democrats against each other.

The Deep South state has used jungle primaries since 1975, with the exception of a three-year span for congressional elections.

A closed primary is when GOP-only and Democrat-only contests are held, and the winners face each other in the general election. In addition, voters must be a registered party member to vote in their primary.

Proponents of the closed primary argue that it is only fair to let registered party voters pick who their party nominee will be. Opponents say the change would cause voter confusion, result in spending additional millions of dollars on elections and that debate over changing primary systems should occur during the regular legislative session in March, not the short special session focused on redistricting.

Landry made his stance on the issue clear during the first day of Louisiana’s special session on Monday. The new governor described Louisiana’s current primary system is a “relic of the past.”

“If you choose to join a political party, it certainly is only fair and right that you have the ability to select your party’s candidates for office, without the interference of another party or without the distraction and the interference of a convoluted, complicated ballot to wade through and decipher,” Landry said.

The bill passed in the House 64-40 and will move to the Senate for debate.