PORTLAND – Measure 65 proponent Phil Keisling argued vehemently that if Oregon adopted an open primary system, it would get rid of the extreme partisanship voters are experiencing this election cycle.

“You know how current system works, you know what it produces. It produces hyper-partisanship, and you know it produces far too little in terms of constructive conversation,” Keisling told Portland City Club members at a debate Friday afternoon. “Measure 65 is a system that lets every voter vote for the candidate that they think is best.”

Keisliing, who was Oregon’s Democratic secretary of state from 1991-1999, teammed up with former Republican Secretary of State Norma Paulus, who served from 1977-1985, to replace the current primary system with the open primary, or “top two” primary.

In a top two primary, voters receive one primary ballot with candidates from all parties listed, and they vote for their top choice. The top two candidates with the most votes, regardless of party affiliation, go on to the general election.

Keisling said that this system would allow for everyone to participate in the primary process so that the two best candidates can advance.

“Why do we have a system that excludes people and doesn’t treat every voter equally?” Kiesling asked. “Is it healthy when young people who register as independents are shut out of primary?”

Reed College professor Paul Gronke argued that the current system allowed for everyone to participate in a primary, so long as they were registered with a party.

“Are you excluded? No, you can affiliate. Those are the rules of the game,” Gronke said. “There is no evidence this system drives away voters.”

Gronke also acknowledged the hyper-partisanship of the current election, but he was quick to point out that the primary system was not the cause of this partisanship.

“There are many reasons that American politics have changed over 20 years, but party primaries have very little to do with it,” Gronke said. “Measure 65 is a solution that doesn’t fit the problem it’s supposed to solve.”

Oregon voters will get their own say when they begin to receive their ballots next Friday. If passed, Oregon will join Washington, which already uses the open primary system.

A previous version of this article incorrectly spelled Mr. Keisling's last name. We regret the error.