A proposed ballot measure would impose term limits on Oregon legislators and those limits would apply retroactively in most cases.

If voters were to send that measure to the ballot and then approve the limits, it would spell a major change for the Legislature. About two-thirds of senators would be prevented from running again, including Senate President Peter Courtney, D-Salem. In the House, more than quarter of members would be affected, among them Speaker Tina Kotek, D-Portland.

The Oregon Supreme Court ruled Thursday that Attorney General Ellen Rosenblum must rewrite the ballot measure's title to make it more accurate.

The measure, called Initiative Petition 19, would limit Oregon lawmakers to eight years in office during any 12-year period. The petition's chief sponsors are Salem physician and former Republican gubernatorial candidate Bud Pierce and his wife Selma. They were not available for comment Thursday.

If the sponsors gather enough valid signatures, roughly 115,000, the initiative would be on the November 2018 ballot.

A novel aspect of Initiative Petition 19 is that it would establish retroactive term limits. That means lawmakers who have been in the Legislature eight years or longer would have to vacate their terms early, with exceptions for legislators elected in November 2018 and mid-term senators.

But the ballot measure title, written by Rosenblum's Justice Department, didn't say that term limits established by Initiative Petition 19 would be retroactive. Matt Swanson, an official with the Oregon branch of the powerful Service Employees International Union, asked the state high court to review whether the ballot title was accurate.

Associate Justice Martha Walters wrote the court's opinion. She said Rosenblum must rewrite the ballot title so it says Initiative Petition 19 would establish term limits and that they would be retroactive.

It's important to note in the title that the term limits are retroactive, Walters wrote, because that would tell voters that term limits would affect the Legislature more quickly than if they were not retroactive.

If those term limits come to pass, there would be a major shake-up in the Legislature, as lawmakers with institutional knowledge are forced out. Many of Oregon's most-tenured lawmakers count their lengthy services records as an asset. And, the Legislature's newcomers often look to their more experienced colleagues for guidance on policy and politics.

Oregon voters, however, may find it better to install fresh faces into the Legislature. They have in the past.

The story of term limits in Oregon goes back 25 years.

In 1992, voters approved Ballot Measure 3, which established term limits for the Legislature and Oregon's members of Congress. The Supreme Court ruled federal term limits void in 1995 and the Oregon Supreme Court struck down the rest of the term limit law in 2002 on procedural grounds.

The court has not ruled that term limits themselves are unconstitutional. Some of Oregon's highest ranking statewide elected officials -- governor, treasurer and labor commissioner -- are limited to two consecutive terms, but there are no lifetime term limits for those positions.

-- Gordon R. Friedman

503-221-8209; @GordonRFriedman