A two-year legal battle over a Seattle, Washington law allowing Uber and Lyft drivers to unionize was prolonged again this week, after a federal appeals court ruled Friday that it can be challenged under federal antitrust law.

The first-in-the-nation law was unanimously passed by the Seattle City Council in 2015 and sought to give ride-share drivers the opportunity to unionize and bargain for better pay and benefits.

But it was swiftly challenged by business and conservative groups, namely the U.S. Chamber of Commerce, representing Uber and Lyft, the National Right to Work Legal Defense Foundation, and the Freedom Foundation. In a 2016 lawsuit against the city of Seattle, the Chamber of Commerce claimed “the ordinance will burden innovation, increase prices, and reduce quality and services for consumers.”

One legal challenge was dismissed last year, but the law remained on hold until other legal challenges were resolved. On Friday, three judges on the 9th U.S. Circuit Court of Appeals unanimously agreed that Seattle’s law is not exempt from the Sherman Antitrust Act, sending it back to U.S. District Court.

Uber spokesman Caleb Weaver called the decision “a win for rideshare drivers, riders and the entire Seattle community.”

The Teamsters Local 117 and members of the App-Based Drivers Association (ABDA) expressed their frustration and disappointment in the wake of Friday’s ruling.

“Anti-trust laws were put in place to protect the little guy from monopolistic practices from large corporations, not to shield a company like Uber — valued at over $70 billion — from negotiating with its workers over fair pay and working conditions,” said Don Creery, Uber and Lyft driver and member of the ABDA leadership council.

One bright spot for proponents of Seattle’s law: the Ninth Circuit judges agreed in their ruling that the National Labor Relations Act (NLRA) can cover independent contractors, like Uber and Lyft drivers.

This week, Sen. Bernie Sanders (I-VT), along with other Senate Democrats, introduced legislation that would make it easier for people working in the gig economy to prove they are employees and thus be able to organize and collectively bargain. While the legislation doesn’t stand a chance in the current Republican-controlled Congress, Bloomberg notes that it has the backing of potential Democratic presidential candidates and could be a sign of things to come if Democrats are able to regain control of either chamber this fall.

This article was originally published at ThinkProgress on May 13, 2018. Reprinted with permission. 

About the Author: Kiley Kroh is a senior editor at ThinkProgress.