The Hain Celestial Group, Inc., et al., Petitioners v. Sarah Palmquist, Individually and as Next Friend of E.P., a Minor, et al.

The Court said a federal court cannot keep a case that was wrongly removed from state court without complete diversity (all plaintiffs from different states than all defendants). It also said dismissing a nondiverse party later under Rule 21 cannot fix that original problem.

The Court ruled 9-0, with Justice Sotomayor writing for the Court.

Majority

Sotomayor

Roberts

Thomas

Alito

Kagan

Gorsuch

Kavanaugh

Barrett

Jackson

“Rule 21 does not permit overriding a plaintiff's choice of state forum in product liability cases.”

This keeps defendants from using a later dismissal to lock a product-liability case into federal court when it should have stayed in state court. Families and companies fighting over where a case belongs will now face a clearer rule about improper removal.

Lower courts must apply this rule when defendants remove cases based on diversity jurisdiction (federal power over cases between citizens of different states). Parties in similar cases will now argue early over whether removal was valid from the start, and wrongly removed cases may return to state court.

The dispute was whether a federal court could keep a case removed from state court when complete diversity was missing at removal. The Court said no.

Product-liability plaintiffs and corporate defendants are directly affected when they fight over forum choice. A later dismissal cannot rescue an improper removal to federal court.

Lower courts must follow this rule in future removal disputes. Litigants will challenge jurisdiction earlier, and some cases may be sent back to state court.