It’s an odd thing to be forced to pay for something you disagree with. It’s worse to be told it must stay that way for the sake of somebody else’s reputation.

Yet that is what the left-leaning justices on America’s Supreme Court are saying.

The court heard arguments last week in a case brought against the California Teachers Association by Rebecca Friedrichs and nine other teachers from the state who argue that being forced to pay “fair-share fees” to a union whose politics they disagree with violates their right to free speech under the First Amendment.

Back in 1977, the Supreme Court decided that while unions cannot force anyone to pay for their political activities, states can allow unions to collect compulsory fees to support their collective bargaining efforts.

The plaintiffs argue that such negotiations are inherently political.

It will certainly seem that way to a liberal-minded worker when a union demands higher wages even if the employer can’t afford any. A sensible union would show restraint in the long-term interest of the employees, but not all trade unions are so sensible.

The right-leaning majority on the Supreme Court appears to sympathize. Justice Samuel Alito has previously called the 1977 decision “something of an anomaly.” Anthony Kennedy, often the court’s swing vote, has pointed out that non-union teachers who oppose seniority-based salaries nevertheless end up financing unions’ “public-relations” (political?) campaigns against merit pay.

But Justice Stephen Breyer ventured an odd argument against overturning the original decision, wondering “what happens to the country thinking of us as a kind of stability” if the court were to “overrule a compromise that was worked out over forty years.”

There is something to Breyer’s argument. Legislation and regulation must be predictable so companies and individuals can make long-term plans. But that can never be an excuse for not righting a wrong.

Forcing workers to pay dues even if they’re not union members — whatever the money is used for — is wrong. The Supreme Court made a mistake forty years ago. It should rectify it this year, rather than let its own credibility weigh against the plaintiffs.