The Washington State Supreme Court held that the Court of Appeals has authority to allow nonparty intervention in criminal appeals when the nonparty previously intervened at trial on the same issue, according to an en banc decision filed Aug. 28, 2025.
In *State v. Thompson* (No. 103338-9), the court addressed whether appellate courts can permit third parties to intervene in criminal appeals under specific circumstances. Justice Mungia wrote for the court that such intervention is permissible when limited to the same issue addressed at the trial level.
The case arose when defendant Lester Thompson Jr. moved to subpoena the medical records of decedent Destinie Gates-Jackson, who was the victim in the criminal case. Jeri Gates, as survivor of Gates-Jackson, intervened at the trial level to object to Thompson's motion for the medical records.
Crucially, Thompson did not object to Gates' intervention at the trial court level. According to the opinion, Thompson "agreed that Ms. Gates had the right to oppose his motions." This lack of objection became significant to the court's analysis of whether intervention should be permitted on appeal.
The trial court denied Thompson's motions to obtain the medical records, but the case proceeded to the appellate level where questions arose about Gates' continued participation in the proceedings.
The Supreme Court's holding clarifies an important procedural question that affects how third parties can participate in criminal appeals. The decision establishes that nonparty intervention in appellate proceedings is not automatically prohibited in criminal cases, contrary to what some might assume based on the generally bilateral nature of criminal prosecutions between the state and defendant.
The court's analysis focused on the continuity between trial and appellate proceedings. By allowing intervention at trial on a specific issue, courts create a foundation for continued participation on appeal regarding that same matter. This approach maintains consistency in legal proceedings while protecting the interests that justified intervention at the trial level.
The case highlights the intersection of criminal procedure with privacy rights, particularly medical privacy protected under the Health Insurance Portability and Accountability Act (HIPAA). The court noted that Gates-Jackson's privacy rights survive in her representative under federal regulations, specifically 45 C.F.R. § 164.502(f) and (g)(1).
This privacy component adds another layer to the intervention analysis. When medical records or other protected information become the subject of discovery disputes in criminal cases, survivors and representatives may have distinct legal interests that justify their participation beyond the traditional prosecution-defense framework.
The en banc nature of the decision indicates the Washington Supreme Court viewed this as a matter of statewide importance requiring full court consideration. En banc decisions carry particular weight as precedent and signal that the court wanted to provide clear guidance to lower courts facing similar intervention questions.
The holding provides important clarity for trial courts considering motions to intervene in criminal cases. Courts can now permit intervention with confidence that the intervening party can continue to participate on appeal regarding the same issue, creating procedural efficiency and consistency.
For defense attorneys, the decision confirms that unopposed intervention at trial may create ongoing participatory rights for third parties on appeal. This could influence strategic decisions about whether to object to intervention motions, particularly when the intervention relates to discovery of sensitive materials.
Prosecutors may also need to consider how third-party intervention affects case strategy and appellate proceedings. While the state typically handles appeals independently, intervening parties may present additional arguments or perspectives that could influence appellate outcomes.
The decision also has implications for victims' rights and privacy protection in criminal proceedings. By clarifying intervention standards, the court has provided a pathway for victims' survivors and representatives to protect privacy interests that might otherwise lack adequate representation in the adversarial criminal justice system.
Legal practitioners handling criminal appeals involving intervention questions now have clear precedent from Washington's highest court. The decision should reduce uncertainty about intervention authority and provide a framework for evaluating similar situations in future cases.
The *Thompson* decision represents a measured approach to balancing the traditional bilateral structure of criminal proceedings with recognition that third parties may have legitimate interests deserving protection. Rather than creating broad intervention rights, the court limited its holding to situations where intervention occurred at trial on the same issue presented on appeal.
This limitation ensures that the decision does not fundamentally alter criminal appellate procedure while still protecting established intervention rights. The approach maintains judicial efficiency by preventing new intervention attempts on appeal while preserving continuity for existing intervening parties.