A divided Supreme Court overturned a decades-old precedent that allowed unions to collect fees from teachers and other public-sector employees who were not in the union, dealing a financial blow to unions that often back Democratic candidates.

The 5-4 opinion in the major labor case was not a surprise. Conservatives on the court have for years expressed a willingness to overturn the 1977 ruling on the idea that requiring the fees forces employees who disagree with the union to subsidize its activities.

This time, Illinois state employee Mark Janus argued the fees public-sector unions collect from nonmembers to cover the cost of actions that help all employees are coerced speech that violate his First Amendment rights.