We’ve been covering constitutional amendments passed in four states that guarantee a secret ballot in all union elections. Shortly after the amendments were enacted, the NLRB challenged Arizona’s amendment in court, arguing that it was preempted by the National Labor Relations Act.

The Board brought a facial challenge to the law—which had not yet been invoked in state court—arguing that the state’s attempt to regulate union elections was preempted by the NLRA. In a decision issued yesterday, the United States District Court for the District of Arizona rejected the NLRB’s argument that the amendment was, on its face, preempted by the Act. The court noted that while “it is possible that state litigation invoking Article 2 s. 37 may impermissibly clash with the NLRB’s jurisdiction,” it could not find the amendment preempted on its face. Such a challenge will have to wait until the law is actually applied.

The NLRB almost certainly will appeal this decision, as well as possibly bring an as-applied challenge if and when the amendment is invoked for the first time. Stay tuned.