A truckers' union strike in the US was handed a setback by the US Supreme Court on Thursday after the latter sided with a Washington State concrete business that sued the union representing its truck drivers after a work halt.

Glacier Northwest Inc. which sells ready-mix concrete, filed a lawsuit in the Washington State court accusing the union representing the International Brotherhood of Teamsters, of deliberate property destruction during a 2017 strike.

The 8-1 decision overturned the ruling that said the lawsuit filed by Glacier Northwest Inc, against a local affiliate of the International Brotherhood of Teamsters, was preempted by a US law called the National Labor Relations Act.

This was the result of a group of drivers going on strike while their trucks were filled with concrete. Even though the mixing drums were kept in rotation to keep the concrete from hardening, the company was forced to throw away the unused concrete at a financial loss.

In 2021, the Washington state Supreme Court ruled that the claims were preempted by the National Labor Relations Act (NLRA), clarifying that the loss was incidental due to a strike that could be considered protected under federal labor law.

'Risks to the right to strike'

Ruling conservative Justice Amy Coney Barrett stated that the union not only destroyed the concrete but had also "posed a risk of foreseeable, aggravated, and imminent harm to Glacier's trucks."

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"Because the union took affirmative steps to endanger Glacier's property rather than reasonable precautions to mitigate that risk, the NLRA does not arguably protect its conduct," Barrett added.

However, liberal Justice Ketanji Brown Jackson wrote that the ruling "is likely to cause considerable confusion among the lower courts" regarding how preemption under the NLRA should be used in future cases and "risks erosion of the right to strike."

The Supreme Court has been diverting toward curbing the power of labor unions in rulings recently. 

A California agricultural regulation helping unions organize workers was struck down by the Justices in 2021 after the court in 2018 ruled that non-members cannot be forced to pay unions representing public employees like police and educators that negotiate collective bargaining deals with employers.

The lawyer representing Glacier Northwest Noel Francisco said that the ruling "vindicates the longstanding principle that federal law does not shield labor unions from tort liability when they intentionally destroy an employer's property", while Teamsters General President Sean O'Brien stated the Supreme Court had "again voted in favor of corporations over working people."

"The ability to strike has been on the books for nearly 100 years," he said, adding: "and it's no coincidence that this ruling is coming at a time when workers across the country are fed up and exercising their rights more and more."

The strike was claimed by the union, Teamsters Local Union No. 174, to be arguably protected under federal labor law but the loss of concrete was unsatisfactory to override federal preemption.

Although it was found by the Supreme Court that labor unions can be sued in state court for threatening conduct, the union saw that this exception should not permit property damage claims under state law.

The justices have been urged by US President Joe Biden to reverse the decision, allowing Glacier Northwest's lawsuit to proceed.

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