Document ID: ./input/supremecourt_opinions/opinions/boundvolumes/529bv.pdf
Page Number: 184.0

529US1

Unit: $U35

[09-26-01 09:32:43] PAGES PGT: OPIN

Cite as: 529 U. S. 89 (2000)

109

Opinion of the Court

under appropriate circumstances. At the same time, as we
also discuss below, uniform, national rules regarding general
tanker design, operation, and seaworthiness have been man-
dated by Title II of the PWSA.

The Ray Court conﬁrmed the important proposition that
the subject and scope of Title I of the PWSA allows a State
to regulate its ports and waterways, so long as the regula-
tion is based on “the peculiarities of local waters that call for
special precautionary measures.” 435 U. S., at 171. Title I
allows state rules directed to local circumstances and prob-
lems, such as water depth and narrowness, idiosyncratic to
a particular port or waterway.
Ibid. There is no pre-
emption by operation of Title I itself if the state regulation
is so directed and if the Coast Guard has not adopted regula-
tions on the subject or determined that regulation is unnec-
essary or inappropriate. This principle is consistent with
recognition of an important role for States and localities in
the regulation of the Nation’s waterways and ports. E. g.,
Cooley, 12 How., at 319 (recognizing state authority to adopt
plans “applicable to the local peculiarities of the ports within
It is fundamental in our federal structure
their limits”).
that States have vast residual powers. Those powers, un-
less constrained or displaced by the existence of federal au-
thority or by proper federal enactments, are often exercised
in concurrence with those of the National Government. Mc-
Culloch v. Maryland, 4 Wheat. 316 (1819).

As Ray itself made apparent, the States may enforce rules
governed by Title I of the PWSA unless they run counter to
an exercise of federal authority. The analysis under Title I
of the PWSA, then, is one of conﬂict pre-emption, which
occurs “when compliance with both state and federal law
is impossible, or when the state law ‘stands as an obstacle
to the accomplishment and execution of the full purposes
and objective of Congress.’ ” California v. ARC America
Corp., 490 U. S. 93, 100–101 (1989) (citations omitted).
In
this context, Coast Guard regulations are to be given pre-