Congress passed the Wild
Free-Roaming Horses and Burros Act (Pub.L.
92-195), which made it a crime to
"capture, brand, harass, or kill" wild horses or burros on
Federal land.
The New Mexico Livestock Board
(NMLB) didn't like the law, so they went onto some Federal land in New
Mexico, captured some burros, and sold them off. The Bureau of Land
Management (BLM) demanded their return. NMLB sued for an injunction.
NMLB argued that 92-195 was unconstitutional unless the Federal
government could show that the horses and burros were items of interstate
commerce (and thus covered by the Interstate Commerce Clause).
New Mexico had its own State
law (New Mexico Estray Law) that
said it was ok to take wild burros.
The Trial Court found for the
NMLB. BLM appealed.
The US Supreme Court reversed.
The US Supreme Court found
that the Federal government has "complete power" over Federal
lands.
Because of the Property
Clause (Article IV, §3, cl. 2),
which gives Congress the power to "dispose of and make all needful
Rules and Regulations respecting the Territory or other Property
belonging to the United States."
The Court found that the
power to regulate wildlife was included in that power to regulate.
New Mexico argued that
wildlife wasn't Federal property and so shouldn't be governed by the Property
Clause. But the Court found that
wildlife was an indispensable part of the ecosystem, so protecting the
animals is a part of protecting the land, even if the Federal government
didn't technically 'own' the wildlife.
Technically, the horses
were introduced by the Europeans and weren't a natural and
indispensable part of the ecosystem.
The Court found that the Supremacy
Clause (Article IV, §2)
overrides any conflicting State laws in areas where Congress has acted.
The Court noted that New
Mexico could still regulate Federal lands, but as soon as Congress
enacted a law on point, then any State laws are preempted.