Nonunion government workers who won a Supreme Court decision last year exempting them from paying unions for the cost of representing them at the bargaining table are not entitled to refunds of the dues they’ve already paid, a federal appeals court ruled Thursday.

The high court ruled 5-4 in June 2018 that the so-called agency fees authorized by law in about two dozen states, including California, violated the First Amendment rights of nonunion members by requiring them to provide financial support to unions. The court overturned its own decision in 1977 that had allowed public employee unions to collect dues from nonmembers to cover collective bargaining costs, though not to fund a union’s political activities.

Nonunion members then filed damage suits to recover past dues payments, sums estimated by their lawyers at more than $120 million nationwide. The suits have been unsuccessful in lower federal courts so far, and on Thursday the Ninth U.S. Circuit Court of Appeals in San Francisco became the second appellate circuit to reject the nonmembers’ claims.

The union that collected the fees in this case, representing public employees in Washington state, “acted in reliance on longstanding bedrock precedent” from more than 40 years ago, Judge Jacqueline Nguyen said in the 3-0 ruling. “The union was not required to forecast changing winds at the Supreme Court.”

She acknowledged that nonunion members “suffered a constitutional wrong for which they may have no viable means of compensation.” But, Nguyen concluded, “it would not be equitable to order the transfer of funds from one innocent actor to another, particularly where the latter received a benefit” in services from the union.

She said the ruling was part of “a growing consensus of courts around the nation,” including a pair of decisions last month by the Seventh U.S. Circuit Court of Appeals in Chicago, where the Supreme Court case originated. Plaintiffs in the Chicago case have asked for a rehearing before the full appeals court and, if unsuccessful, could seek review again in the Supreme Court.

A lawyer for nonunion members declined to comment on Thursday’s ruling. When the original reimbursement claim was filed, attorney Bill Messenger of the National Right to Work Legal Defense Foundation said, “We’re just asking that the money be returned to its rightful owner.”

Last year’s ruling, in a case called Janus vs. AFSCME, struck a potentially severe financial and political blow to public employee unions and the candidates, mostly Democrats, they support. But union leaders maintain they have used education and recruitment campaigns to avert the predicted large-scale departure of members seeking to lower their costs.

“It’s pretty remarkable it hasn’t caused members to drop, or the feared financial impact,” said Edward Younglove, a lawyer for the union in Thursday’s case. He said unions had known they would lose last year’s case and “did a pretty good job of preparing.”

Bob Egelko is a San Francisco Chronicle staff writer. Email: begelko@sfchronicle.com Twitter: @BobEgelko