Kentucky unions are suing Republican Gov. Matt Bevin for signing a right-to-work law, arguing that the law, which prevents workers from being forced to join or otherwise financially support a union as a condition of employment, violates the state constitution.

Their lawsuit says that the right-to-work law violates the state constitution‘s prohibitions on “takings” without just compensation. In other words, the labor groups are arguing that the law robs them of their property by preventing non-union members from having to pay the union.