A federal judge this afternoon put the brakes on Seattle's unprecedented experiment to allow drivers for ride-sharing companies like Uber to unionize.

United States District Judge Robert S. Lasnik sided with the U.S. Chamber of Commerce today, ordering Seattle's Uber unionization law be put on hold until lawsuits challenging its legality are resolved.

In his order, Lasnik acknowledges the national implications of the case, which could affect not only Uber drivers but many industries that depend on independent contractors.

"The issues raised in this litigation are novel, they are complex, and they reside at the intersection of national policies that have been decades in the making," Lasnik writes. "The public will be well-served by maintaining the status quo while the issues are given careful judicial consideration as to whether the city’s well-meaning ordinance can survive the scrutiny our laws require."

The order stems from a lawsuit filed last month by the Chamber, which argues the law violates federal labor and antitrust laws. As part of that suit, the Chamber asked the judge for a temporary restraining order to halt the law now, before that case is fully resolved.

The Chamber claimed the law posed an immediate threat to companies like Uber and Lyft because it requires them to hand over the names of their drivers to unions hoping to organize drivers.

The Teamsters Union Local 117, which backed the law, now hopes to contact drivers about unionizing but needs their information from the ride-share companies to reach them all. The Chamber argued handing over that information would “wreak irreparable harm that threatens the very existence of the for-hire and rideshare transportation system in western Washington." The names of drivers constituted “confidential” and “trade secret” information, the Chamber claimed. The City of Seattle defended the law, arguing the companies would suffer no harm from handing over those names.

"We knew they were going to do everything they could to stop drivers from having a voice," Teamsters 117 Business Representative Dawn Gearhart tells The Stranger today. "That's not going to stop us from moving forward and advocating for better working conditions."

The Teamsters have been contacting drivers while they wait for the names from Uber and Lyft. So far, they've reached about 2,000 drivers, many of whom drive full-time and depend on the job for their livelihood, Gearhart says. Based on legal documents, the union believes Uber has at least 14,000 drivers in Seattle.

The law, which the Seattle City Council passed in late 2015, has split rideshare drivers in Seattle. Some say they struggle to make ends meet driving for companies like Uber and Lyft and suffer unpredictable working conditions like being kicked off the app for unclear reasons. Others say they make a living wage on the apps or they fear unionization threatens the flexibility they enjoy about driving for Uber or Lyft part-time. Lyft opposed the law as the council considered it, but has stayed largely quiet since then. Uber, meanwhile, has run an aggressive anti-union campaign.

Gearhart says the Teamsters will continue their organizing efforts while the lawsuits wind their way through the courts. Soon, they may ask the Seattle City Council to regulate the rates Uber pays its drivers. A representative for Uber could not immediately be reached for comment. Both Uber and Lyft are praising the decision. In a statement, General Manager for Uber in the Pacific Northwest Brooke Steger said, "We look forward to the court’s full consideration of the many serious legal questions about this ordinance as the lawsuit moves forward.” Lyft spokesperson Adrian Durbin called the unionization law "poorly drafted" and said it "could undermine the flexibility of drivers to choose when, where and for how long they drive." A statement from the Seattle City Attorney's Office emphasized that today's order is not the final word in the lawsuit. The city has asked the court to dismiss the lawsuit.

This case is just one of several lawsuits challenging the law. A group of drivers is also suing in federal court. (In deciding on this order, Lasnik also considered some arguments in the drivers' case.) In King County Superior Court last month, Uber challenged the rulemaking process the city undertook to implement the unionization law. Uber lost that round.