The US supreme court has ruled that government workers cannot be forced to contribute to unions that represent them in collective bargaining, dealing a serious financial blow to organised labour in America.
The court's conservative majority scrapped a 41-year-old decision which had allowed states to require that public employees pay some fees to unions that represent them, even if the workers choose not to join.
The 5-4 decision fulfils a long-standing wish of conservatives to get rid of the so-called fair share fees that non-members pay to unions in roughly two dozen states. Organised labour is a key Democratic constituency.
The court ruled that the laws violate the US Constitution's First Amendment by compelling workers to support unions they may disagree with.
Justice Samuel Alito said in his majority opinion: "States and public-sector unions may no longer extract agency fees from non-consenting employees."
It in the latest case in which Justice Neil Gorsuch, an appointee of President Donald Trump, provided a key fifth vote for a conservative outcome.
Mr Trump himself tweeted his approval of the decision while Judge Alito still was reading a summary of it from the bench.
"Big loss for the coffers of the Democrats!" Mr Trump said in the tweet.
Supreme Court rules in favor of non-union workers who are now, as an example, able to support a candidate of his or her choice without having those who control the Union deciding for them. Big loss for the coffers of the Democrats!— Donald J. Trump (@realDonaldTrump) June 27, 2018
In dissent, Justice Elena Kagan wrote of the big impact of the decision.
"There is no sugarcoating today's opinion," she said.
"The majority overthrows a decision entrenched in this Nation's law - and its economic life - for over 40 years.
"As a result, it prevents the American people, acting through their state and local officials, from making important choices about workplace governance.
"And it does so by weaponising the First Amendment, in a way that unleashes judges, now and in the future, to intervene in economic and regulatory policy."
The court's three other liberal justices joined the dissent.
The court split 4-4 the last time it considered the issue in 2016 following the death of Justice Antonin Scalia. Last year, unions strongly opposed Mr Gorsuch's nomination by Mr Trump.
The unions say the outcome could affect more than five million government workers in about two dozen states and the District of Columbia.
The case involving Illinois state government worker Mark Janus is similar to the one the justices took up in 2016.
At that time, the court appeared to be ready to overrule a 1977 high court decision that serves as the legal foundation for the fair share fees. But Mr Scalia's death left the court tied, and a lower court ruling in favour of the fees remained in place.
The unions argued that so-called fair share fees pay for collective bargaining and other work the union does on behalf of all employees, not just its members.
More than half the states already have right-to-work laws banning mandatory fees, but most members of public-employee unions are concentrated in states that do not, including California, New York and Illinois.
Labour leaders fear that not only will workers who do not belong to a union stop paying fees, but that some union members might decide to stop paying dues if they could in essence get the union's representation for free.