CRS Report for Congress
The Supreme Court Rules Against Corps of
Engineers Jurisdiction over “Isolated Wetlands”:
The SWANCC Decision
Robert Meltz
Legislative Attorney
American Law Division
On January 9, 2001, the Supreme Court handed down the latest in its series of recent
decisions relating to the balance between federal and state power in our dual system of
government. In Solid Waste Agency of Northern Cook County (SWANCC) v. U.S. Army
Corps of Engineers, the Court ruled that the long controversial “migratory bird rule,” used
by the Corps of Engineers to interpret its authority over “isolated wetlands,” exceeded the
agency’s authority under the Clean Water Act (CWA).
Background of the case. SWANCC, a consortium of Chicago cities and villages,
sought to develop a landfill for baled nonhazardous solid waste on a 533- acre parcel in
Illinois. The parcel had been used for sand and gravel mining until about 1960. Since
then, the excavation trenches had evolved into ponds up to several acres in size.
SWANCC obtained the needed local and state permits, but the Corps denied a federal
wetlands permit, required under CWA section 404(a)1 for wetlands within that provision’s
reach. At issue here is the Corps’ assertion that 404(a) covered the SWANCC site,
notwithstanding that the ponds on the site were only “isolated wetlands”– those not
abutting navigable waters of the United States or their tributaries. Long ago, the Supreme
Court upheld the Corps’ authority under section 404 to regulate wetlands actually abutting
a navigable waterway.2 The Corps in SWANCC was asserting jurisdiction over wetlands
not so abutting, as Corps regulations have provided for since 1977.
The Corps’ jurisdiction claim involved three steps. First, section 404 applies by its
terms to “navigable waters,” defined expansively by the CWA to mean “the waters of the
United States.”3 Second, the Corps’ regulation interpreting “waters of the United States”
includes “waters such as intrastate lakes, ... wetlands, ... wet meadows, ... or natural
ponds, the use, degradation, or destruction of which could affect interstate commerce.”
Third, the Corps’ migratory bird rule, a 1986 attempt to clarify the intrastate waters

1 33 U.S.C. § 1344(a).
2 United States v. Riverside Bayview Homes, Inc., 474 U.S. 121 (1985).
3 CWA § 502(7); 33 U.S.C. § 1362(7).
Congressional Research Service The Library of Congress

covered by the regulation, says that such waters include those “which are or would be used
as habitat by ... migratory birds that cross state lines ....” Migratory birds had been
observed on several occasions using the ponds on the SWANCC site.
The U.S. Court of Appeals for the Seventh Circuit found that Congress has the
authority under the Commerce Clause of the Constitution to regulate isolated wetlands,
and that Congress, in enacting section 404, intended to reach such wetlands. The Supreme
Court reversed.
The Supreme Court decision. As with many other Supreme Court decisions involving
the line between federal and state power, the SWANCC ruling saw the Court divide along
5-4 lines. The five-justice majority opinion concluded that the migratory bird rule is not
supported by the CWA. It was unnecessary, therefore, for it to reach the second issue:
whether, had the migratory rule been authorized under the CWA, it exceeded Congress’
power under the Commerce Clause.
The majority opinion held that Congress, in enacting 1977 amendments to the CWA,
had not implicitly approved the Corps’ broad definition of “navigable water” adopted that
year (in regulations quoted above) under the original 1972-enacted CWA. For example,
Congress’ failure to pass a bill in 1977 containing a narrow definition of navigable waters
had not been shown by the Corps, said the majority, to constitute congressional approval
of the Corps’ broad definition. The majority then declined to afford the Corps the
customary deference granted agency interpretations of ambiguous statutes. For one thing,
it said, section 404 is not ambiguous at all. And even if it were, deference is not
appropriate where an agency interpretation of a statute “invokes the outer limits of
Congress’ power” – a reference to the Court’s milestone decisions in recent years
involving the reach of the Commerce Clause. This concern is particularly strong, it said,
where the agency interpretation permits encroachment on a traditional state power – here,
that over land and water use.
Implications of the decision. The SWANCC decision continues the efforts of the
five justices generally regarded as conservative to limit federal regulatory power. In 1985
and 2000, these same five justices found that Congress had exceeded Commerce Clause
limits in enacting legislation dealing with possession of guns in school zones and violence
against women. While SWANCC did not reach the constitutional question, its analysis of
the CWA has, as noted, an explicit undercurrent of constitutional and federalism concerns.
The next event to watch will be the Court’s decision whether to grant the petition for
certiorari in a Commerce Clause challenge to the Endangered Species Act.4
SWANCC’s implications for the scope of the federal wetlands permitting program are
not fully clear. The holding in SWANCC is limited to invalidating the migratory bird rule,
and thus appears to be narrower than the rationale supporting it. As a result, the degree
of program contraction may depend on which of these the government decides to apply.
In either event, continuing program coverage is certain for the majority of wetland acreage
– that which is adjacent to navigable waters or their tributaries – and possible as well for
wetlands adjacent to some large intrastate waterbodies.

4 Gibbs v. Babbitt, 214 F.3d 483 (4th Cir. 2000), petition for cert. filed, 69 U.S.L.W. 3383 (Nov.

22, 2000) (No. 00-844).