Striking Amazon Drivers Cue Up Labor Battle Over Picket Rights

The Teamsters’ multistate strike against Amazon.com Inc. involving thousands of contract delivery drivers lays the groundwork for battles over whether those drivers can legally mount protests to force the company to the bargaining table.

Amazon, which has already filed unfair labor practice charges accusing the International Brotherhood of Teamsters of unlawful strike behavior, could press the argument that the drivers are engaging in unlawful “secondary boycotts” under federal labor law and seek monetary damages, legal observers said.

But that claim would hinge on whether the online retail giant is a “joint employer” of the drivers, who were hired by third-party ...