The U.S. Supreme Court’s Wednesday ruling to prohibit mandatory union dues for public employees could affect more than 400,000 workers in Oregon and Washington.

The widely anticipated 5-4 decision is a big setback for the public employee unions that are major political forces in the two states. The decision could lead to a decline in the number of workers who pay dues and in campaign spending by organized labor.

In this Monday, June 25, 2018, photo, people gather at the Supreme Court awaiting a decision in an Illinois union dues case, Janus vs. AFSCME, in Washington. The Supreme Court says government workers can't be forced to contribute to labor unions that represent them in collective bargaining, dealing a serious financial blow to organized labor.

In this Monday, June 25, 2018, photo, people gather at the Supreme Court awaiting a decision in an Illinois union dues case, Janus vs. AFSCME, in Washington. The Supreme Court says government workers can’t be forced to contribute to labor unions that represent them in collective bargaining, dealing a serious financial blow to organized labor.

J. Scott Applewhite/AP

The court ruled in Janus v. AFSCME that state and local government workers represented by organized labor no longer have to pay “fair-share” fees if they don’t want to belong to a union.

Oregon and Washington are among 22 states around the country that require workers to pay “fair-share” dues — even if they opt out of joining a union. Another state, Missouri, had scheduled an August vote on whether to go ahead with legislation that abolished mandatory dues.

Oregon has about 145,000 government workers covered by union contracts while Washington has more than 290,000, according to Unionstats.com, an academic website that tracks union membership. 

Workers who decline to join the unions that represent them are required to pay fees that aren’t supposed to include costs of political activities. Typically, those fees are about 80 percent of what union members pay.

For more than two years, organized labor has braced itself for a ruling of this kind from the Supreme Court. The court had appeared to be ready to rule against the unions until Justice Antonin Scalia died in early 2016, leaving the remaining justices deadlocked 4-4.

Several top Oregon union officials said in a telephone press conference Wednesday that they are confident they can persuade workers it is in their best interests to stay with organized labor.

“Today is a day of revitalization of the labor movement,” said Oregon AFL-CIO President Tom Chamberlain. 

“Members of Oregon’s public unions are joining members across the country to declare their resolve to stick together.”

“Oregon’s unions will continue to flourish,” added Melissa Unger, executive director of the state’s largest union, Local 503 of the Service Employees International Union.

She said her union has been able to continue increasing its membership of home care workers, despite the fact that a previous Supreme Court ruling eliminated mandatory dues for that segment of the workforce. However, union critics predicted large drops in union membership.

Aaron Withe, Oregon director of Freedom Foundation, said his group would run a major media campaign telling workers they can opt out of paying union dues.

“We anticipate membership to be declining between 20 percent and 30 percent in the next 12 months,” said Withe, who said it would not be inaccurate to call his group anti-union.

His is one of many groups backed by business and conservative interests that have chafed at the political power of public employee unions. These labor organizations have grown over the last four decades while private union membership has declined.

In Oregon, according to Unionstats.com, just over half of all public employees belong to a union, compared to just 8.3 percent of the workforce.

In Washington, about 12 percent of the private workforce is in a union, compared to just over half of public workers. Public employee unions run sophisticated operations in both states that lean to the left politically.

In Oregon, for instance, the unions created a year-round political operation, Our Oregon, that serves as an organizing tool for several progressive groups.

In 2016, Our Oregon put a major business tax proposal, Measure 97, on the state’s ballot and raised nearly $17 million for the campaign — almost all from public employee unions.

Business groups contributed far more in opposition and the measure failed at the polls.

But in the same year, the unions did play a key financial role in helping the Democrats maintain control of the Oregon Legislature and gain full control of the Washington Legislature.

Liz Craig, a spokeswoman for Oregon’s Department of Administrative Services, said the state is looking at the process for ending the fees paid to unions by non-members. She said the two largest state employee unions — SEIU and the American Federation of State, County and Municipal Employees — have been receiving fair-share fees from about 6,100 workers.

Altogether, more than 23,000 state workers are union members. Meanwhile, the Oregon School Boards Association told districts it is drafting guidance for how they should proceed.

Even before the Janus decision, union foes filed two lawsuits in Oregon arguing against compulsory union dues for public employees.

One of them is on behalf of Debora Nearman, a state Department Fish and Wildlife employee who is married to Rep. Mike Nearman, R-Independence.

She is represented by Local 503 and charges that her constitutional rights are being violated because she was forced to support the union at the same time it was spending more than $50,000 in an unsuccessful effort to defeat her husband in 2016.

Jill Gibson, a Portland attorney representing Nearman, said she was still studying whether there was any reason for her to proceed with the lawsuit given the extent of the Janus decision. She predicted that a wave of workers would quit the unions as word of the ruling spreads.

Most Republican officials in the state — including GOP gubernatorial nominee Knute Buehler — didn’t rush to comment on the Janus ruling. But Democratic leaders, who depend heavily on union support, were quick to attack the ruling and praise the role of organized labor.

Democratic Gov. Kate Brown issued a statement with three labor leaders saying that unions are in the forefront of “fights to raise the minimum wage, ensure that women and people of color are paid equally and treated fairly in the workforce, and expand access to affordable healthcare.”