(Daniel Mears/Detroit News via AP)

Despite opposition from members of both parties, proponents of an Oregon ballot measure that would makes the state’s primaries nonpartisan have raised more than $1 million.

Measure 90 is the second attempt to introduce a top-two open primary in Oregon in the past six years. If passed, it would replace Democratic and Republican primaries with a statewide primary open to all voters, and the top two candidates from that primary, regardless of affiliation, would then progress to the general election.

A similar initiative made it to the ballot in 2008, but about two-thirds of the voters voted against it. Maurice Henderson, campaign manager for Every Oregon Voter Counts, said he believes things will be different this time.

“I think we’ve got changing headwinds,” Henderson said, citing the support of Gov. John Kitzhaber (D), and the handful of current and former Republican and Democratic lawmakers who’ve endorsed the measure.

They’re are also bringing in a lot more cash.

Associated Oregon Industries, one of the state’s top business lobby groups, is the latest to donate to support the measure, giving a $50,000 cash contribution, according to the Oregon Secretary of State’s office. Every Oregon Voter Counts has raised more than $1 million, including donations from Columbia Sportswear CEO Tim Boyle and the Papé group, which sells equipment for agriculture, construction and other industries. Henderson also said the group has had conversations with the Bloomberg Foundation.

Despite the donations, the measure faces stiff opposition. “Both parties have come out against it,” Henderson said.

Last week, the Oregon Republican Party Executive Committee voiced its opposition to the initiative, calling it “un-American” and arguing that it violates free speech and the right to vote. The state party could make a statement on whether or not it supports the measure as soon as Aug. 23, said Art Robinson, party chairman.

Robinson said there’s a variety of reasons Republicans could support or oppose the measure, but one argument he’s heard frequently is concern over whether it would disrupt party organization at the local level.

“I think of of the greatest concerns is ‘we don’t know what this is going to do to us, let’s stick with what we know,’ ” he said.

California, Louisiana and Washington have open top-two primaries, according to the National Conference of State Legislatures.

Correction: An earlier version of this article included incorrect information about a company that collected signatures for the measure.