In the 1998 case of Naomi Marquez v. Screen Actors Guild, Inc., et al., Marquez sued the Screen Actors Guild (SAG) and multiple talent agencies for alleged violations of antitrust laws. She claimed that SAG's "exclusive bargaining agent" status allowed it to unfairly control access to employment opportunities in Hollywood by enforcing a franchising agreement with talent agencies, which she argued was anti-competitive. The Supreme Court ruled against Marquez, stating that her claims were preempted by federal labor law under the National Labor Relations Act (NLRA). The court held that because SAG was acting as an exclusive bargaining representative - a role specifically sanctioned and regulated by NLRA - its actions could not be challenged under antitrust laws. Furthermore, they found no evidence suggesting Congress intended for antitrust laws to apply in such situations.

In the dissenting opinion for Naomi Marquez v. Screen Actors Guild, Inc., et al., it was argued that the majority's decision to dismiss Marquez's claim against her union and employer under Section 301 of the Labor Management Relations Act (LMRA) was incorrect. The dissent believed that Marquez had a valid claim because she alleged that her union breached its duty of fair representation by failing to inform her about certain provisions in a collective bargaining agreement which affected her employment rights. They contended that this failure constituted an unfair labor practice under federal law, thus making it actionable under Section 301 of LMRA. Furthermore, they disagreed with the majority’s view on preemption doctrine and asserted there should be no distinction between substantive rights created by collective agreements and procedural ones when considering if state claims are preempted by federal law.