Wisconsin Public Intervenor v. Mortier

Background

The dispute involved the small rural town of Casey, Wisconsin, which adopted an ordinance requiring permits for pesticide applications, including rules for aerial spraying, advance notice, placards, hearings, and fines. A landowner, Ralph Mortier, and a coalition of pesticide users sued, arguing the town’s ordinance was overridden by federal law (FIFRA) and state law. Lower courts ruled the ordinance was pre-empted; the Wisconsin Supreme Court agreed by 4–3, and the U.S. Supreme Court agreed to review the case.

Reasoning

The high court addressed whether the federal pesticide statute prevents local governments from regulating pesticide use. The majority held that FIFRA’s text does not expressly bar municipal rules and that the legislative history is mixed and therefore insufficient to show a clear and manifest congressional intent to preclude local regulation. The Court found FIFRA did not occupy the whole field, left room for state and local supplementation, and detected no direct conflict between Casey’s ordinance and FIFRA.

Real world impact

The decision allows towns and other local authorities to adopt and enforce local permit schemes and other use restrictions unless those rules physically conflict with federal or state law or stand as an obstacle to federal objectives. Farmers, pest control businesses, and local governments are affected. The case was remanded for further proceedings consistent with the Supreme Court’s ruling.

Dissents or concurrances

Justice Scalia concurred in the judgment but emphasized that committee reports pointed more clearly toward pre-emption; he warned against relying on legislative history to supply binding meanings and argued the statutory text should control.