Unions are extremist groups, and candidates supported by unions shouldn’t be trusted by voters.

At least, that’s the basic message of several Republican political campaigns in Oregon, which are slamming Oregon Democrats for getting support from unions.

Republican State House campaigns for Karen Minnis, Bruce McCain and Donna Nelson used that approach against Democratic opponents Rob Brading, Jeff Merkley and Sal Peralta, respectively.

In truth, unions remain a potent force in politics, but their contributions are dwarfed by those of business interests (by more than 10 to 1) — a fact that’s absent from the Republican campaign mailers.

“Oregon’s big labor unions are dumping tens of thousands of dollars into Rep. Jeff Merkley’s campaign,” said an ad mailed to constituents in the incumbent’s East Portland House District 47. Listing contributions by the Service Employees (SEIU), Oregon Education Association (OEA) and the Oregon School Employees Association, the ad asks, “What has Merkley promised these extreme groups?”

In Yamhill County, supporters of incumbent Republican Representative Donna Nelson accused challenger Sal Peralta, a Democrat, of getting almost all his support from big unions and Portland special interest groups. The accusations came in phone calls to House District 24 voters. The charges angered Peralta because he had made a campaign pledge to refuse all contributions from businesses or unions outside his district, and, in fact, returned checks from the Pacific Northwest Regional Council of Carpenters and the United Steelworkers, even though both have locals in his district.

And in Oregon’s highest-profile legislative race between incumbent Karen Minnis and Rob Brading, the challenger was taken to task for being “bankrolled by big public employee labor unions.” The charges, in a mailing to House District 49 and a television ad, single out Brading’s support from SEIU Local 503 as one of three examples of how Brading is a stooge of “downtown Portland liberals.” Local 503’s Portland office, at 6401 SE Foster Rd., is five miles from “downtown Portland.” Moreover, Minnis is herself supported by several unions, including the 21,000-member American Federation of State, County and Municipal Employees, which contributed $5,000 to her campaign. She also got $26,000 from the Oregon Nurses Association, $7,500 from Electrical Workers Local 48, $2,000 from IBEW Local 280, and $1,000 from Plumbers and Steamfitters Local 290. And she advertised her support from unions in a mailer to union households.

“The hypocrisy drips,” says Jon Isaacs, executive director of Future PAC, which funds Democratic campaigns for the Oregon House. “Here she is, touting her support from Portland’s largest public employees union [AFSCME] and pounding Rob Brading for being bankrolled by a big public employee union.”

For his part, Brading pleads guilty to winning the backing of unions, including the Oregon AFL-CIO, Machinists, OEA, Carpenters, United Food and Commercial Workers and SEIU, which has contributed nearly $54,000 to his campaign, plus in-kind support.

In the final analysis, ads attacking the union money connection don’t work with voters, Isaacs said.

“We tested that message,” Isaacs said. “It’s not an effective argument. It’s essentially an attack on not just union members but all working people.”

Republican campaigns that point the finger at unions “bankrolling” Democrats raise the question of who’s “bankrolling” Republican candidates. It’s a list heavy with corporate names.