Constitutional Limits on States’ Power over Foreign Affairs
Legal Sidebari
Constitutional Limits on States’ Power over
Foreign Affairs
August 15, 2022
The Constitution gives the federal government the primary power to manage the United States’ foreign
relations. Article I, Section 10 prohibits states from engaging in a set of activities that implicate
international affairs, while the Supremacy Clause, Foreign Commerce Clause, and other constitutional
provisions place key elements of this power with the federal government. Interpreting these provisions,
the Supreme Court has described the United States’ foreign affairs power not only as superior to the
states but residing exclusively in the national government. With respect to foreign relations, the Supreme
Court said that “state lines disappear” and the “purpose of the State ... does not exist.”
Despite this sweeping language, states and other subnational entities (e.g., cities and counties) play a
more prominent role in international relations than may be generally recognized. States have offices
overseas and send trade and diplomatic delegations to foreign countries. They have imposed economic
sanctions for human rights abuses and military aggression—most recently on Russia for invading
Ukraine. States regularly enter into written pacts with foreign governments on issues ranging from trade
to the environment to tourism. Some of these international pacts address potentially sensitive subjects,
such as border security with Mexico and technology transfers with the People’s Republic of China (PRC).
A recent rise in pacts with PRC-based bodies led U.S. intelligence officials to warn state and local
governments about PRC efforts to exploit its relationships with subnational governments to promote its
geopolitical interests in the United States.
The Supreme Court has held that the Constitution constrains states’ ability to act on the global stage, but
much of the state-driven international activity is not publicized or presented to Congress. Because
Congress may have an interest in optimizing and overseeing states’ actions in this area, this Sidebar
discusses constitutional limits on states’ role in international affairs and potential avenues for
congressional involvement.
Article I, Section 10
Article I, Section 10 of the Constitution contains a catalog of prohibitions and limitations on states’
power. Many of these restrictions relate to foreign relations. In particular, Clause 1 prohibits the states
from entering into any “Treaty, Alliance, or Confederation.” Clause 3—commonly called the Compact
Clause—requires Congress to approve any state’s “Agreement or Compact” with a “foreign Power,” i.e.,
Congressional Research Service
https://crsreports.congress.gov
LSB10808
CRS Legal Sidebar
Prepared for Members and
Committees of Congress
Congressional Research Service
2
a foreign government. (The Compact Clause also governs interstate agreements and compacts, discussed
in this Sidebar). Whereas Clause 1 categorically prohibits every treaty, alliance, and confederation, the
Compact Clause conditionally allows states to make agreements and compacts, provided Congress
consents. These clauses create a clearly bifurcated structure, yet the founding documents do little to
explain how to distinguish between the treaties banned by Clause 1 versus the agreements and compacts
that may be approved under the Compact Clause.
The Founders apparently believed the distinctions were self-explanatory, but that is no longer the case. In
The Federalist No. 44, James Madison wrote that the “particulars” of Article I, § 10 “are either so
obvious, or have been so fully developed, that they may be passed over without remark.” Despite
Madison’s confidence, the meaning of these terms of art were “lost” within a generation, according to the
Supreme Court. Jurists and scholars have debated several theories of how to distinguish Clause 1’s
treaties from the Compact Clause’s agreements and compacts, but no authoritative approach has emerged.
Other than stating that the Civil War Confederacy violated Clause 1, the Supreme Court has provided
little guidance on what constitutes a treaty, alliance, or confederation. By contrast, the Supreme Court has
developed a body of jurisprudence interpreting the Compact Clause, which may inform the constitutional
limits on states’ power to make commitments to foreign governments.
Holmes v. Jennison
Several Justices concluded in an 1840 case that the Compact Clause covers every agreement between
state and foreign governments regardless of the agreement’s form or content. In Holmes v. Jennison, the
governor of Vermont ordered a resident of Quebec (then part of Great Britain) arrested and returned to
Quebec to stand trial for murder even though the United States did not have an extradition treaty with
Britain at the time. A crucial legal issue—whether the Supreme Court had jurisdiction—turned on
whether the governor of Vermont had arrested the fugitive under an informal “agreement” with Canadian
authorities within the meaning of the Compact Clause. The case ultimately ended with an equally divided
court, but four Justices found that the governor made an agreement that should have been submitted to
Congress for consent. This four-Justice opinion, written by Chief Justice Taney, was based on a literal
interpretation of the Compact Clause that would require congressional approval for “every agreement,
written or verbal, formal or informal, positive or implied, by the mutual understanding of the parties.”
Although not a majority opinion, Chief Justice Taney’s reasoning has been influential, and the Supreme
Court cited it positively in later cases. At the same time, historical practice does not support the view that
all agreements between states and foreign governments require Congress’s consent. Scholars have shown
that states rarely seek congressional approval for pacts with foreign governments. Moreover, in the
context of interstate compacts, the Supreme Court developed a new line of cases that more narrowly
interpreted the congressional consent requirement than Chief Justice Taney’s Jennison opinion.
Applying Interstate Compact Cases
Beginning with Virginia v. Tennessee in 1893, the Supreme Court declined to adopt Chief Justice Taney’s
literal reading of the Compact Clause. Instead, the Court used a functional interpretation that limited the
congressional consent requirement. Under Virginia and later interstate compact cases, only interstate
compacts that have the potential to increase states’ political power at the expense of federal sovereignty
require congressional consent. In a 1985 case, the Supreme Court stated that only state commitments that
have certain “classic indicia of a compact” require congressional approval.
The Supreme Court has not said whether this interstate compact jurisprudence applies to states’
international compacts. Some observers argue that the two types of compacts raise different concerns and
should not share the same standard. The greater weight of authority, however, suggests that the Court’s
interstate compact cases apply in both scenarios. Several courts and the executive branch have applied
Congressional Research Service
3
Virginia’s functional test to states’ engagement with foreign governments. For example, a federal district
court in 2020 applied Virginia and its progeny in rejecting a Compact Clause challenge to a California
carbon cap-and-trade agreement with Quebec. Thus, under the current state of the law, only a select set of
state agreements with foreign powers that satisfy the Supreme Court’s interstate compact jurisprudence
require congressional consent.
Supremacy Clause Preemption
Apart from the limitations in Article I, Section 10, the federal government’s preemption power may limit
states’ role in foreign affairs. Under the Supremacy Clause, federal statutes and self-executing
international agreements preempt (i.e., render unenforceable) conflicting state laws. As discussed in this
CRS Report, federal law can expressly preempt state law—or it can impliedly do so—when the
preemptive intent can be inferred from the federal law’s structure and purpose. These preemption
principles can invalidate state statutes that undermine the federal government’s diplomatic and foreign
policy goals.
In Crosby v. National Foreign Trade Council, the Court addressed whether federal law sanctioning Burma
preempted a Massachusetts law that restricted state agencies’ ability to contract with companies doing
business with Burma. Although the laws shared similar foreign policy objectives of addressing human
rights issues in Burma, the Supreme Court held that the Massachusetts law frustrated federal aims by
using stronger economic restrictions and not providing the President the same waiver authority as the
federal statute. The Crosby court reasoned that because the President could not waive the Massachusetts
restrictions even if Burma yielded to the full slate of the United States’ demands in its diplomatic
negotiations, the state law undermined the United States’ ability to present a unified negotiating position.
As a result, the Court held that federal law preempted the Massachusetts statute.
Preemption can also apply when state law undermines the United States’ foreign policy expressed in its
treaties and executive agreements. In American Insurance Association v. Garamendi, the Supreme Court
struck down a California law that required in-state insurers to disclose information about Nazi-era life
insurance policies. In the late 1990s, survivors of the Holocaust and their heirs filed a large number of
lawsuits in U.S. courts seeking to recover the value of insurance policies held in Germany that were never
collected because of Nazi persecution and policies in the 1930s and 1940s. The California law was part of
a broader effort to allow Holocaust survivors and their heirs to make claims related to those Nazi-era
policies in California courts. The United States and Germany, by contrast, believed those claims were best
resolved outside of litigation. The two countries concluded an international agreement designed to allow
Nazi-era insurance claims to be heard before an international claims commission. Because the California
law frustrated the United States’ objectives, the Garamendi Court held it was preempted.
Dormant Commerce Clause
Whereas preemption arises when federal and state law cannot coexist, the Commerce Clause can limit
states’ power even in the absence of a conflict. The Commerce Clause grants Congress the power “[t]o
regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes[.]”
The Supreme Court has interpreted the Commerce Clause both as a positive grant of power to Congress
and as an implied restriction on states’ authority to interfere with interstate and foreign commerce. This
inferred, negative limitation is call the “Dormant” Commerce Clause. Under this limitation, states may
not discriminate against, or impose excessive burdens on, interstate or foreign commerce unless Congress
authorizes them to do so.
In Dormant Commerce Clause challenges, the Supreme Court more heavily scrutinizes state laws that
implicate foreign commerce rather than interstate commerce. According to the Supreme Court, the federal
government sometimes has a “special need for federal uniformity” that requires it to “speak with one
Congressional Research Service
4
voice” and present a unified foreign policy in foreign commerce cases. A state law impermissibly burdens
foreign commerce under the “one voice” standard if the law violates an express federal directive or
implicates foreign policy issues that the Constitution assigns to the federal government.
Zschernig v. Miller
In a 1968 decision, Zschernig v. Miller, the Supreme Court described another constitutional principle,
called the dormant foreign affairs doctrine or foreign affairs field preemption, which can limit states’
power to act on the global stage. In Zschernig, an Oregon resident died without a will, and his sole heirs
were residents of East Germany that sought to inherit the estate’s property. The dispute arose because
Oregon law blocked nonresident aliens from inheriting personal property unless the country where the
alien lived provided reciprocal inheritance rights to U.S. citizens. The Oregon law did not conflict with a
federal statute or international agreement, and the United States submitted a brief saying the law did not
interfere with its foreign affairs. Even with no conflict, the Court scrutinized the Oregon statute to see if it
intruded into a broader “field of foreign affairs” that the Constitution entrusts to the federal government.
The Zschernig Court expressed concern that the Oregon law invited probate courts to examine the internal
affairs of foreign nations—particularly those governed by authoritarian and communist regimes—to see if
the countries allowed free transfer of private property. The Supreme Court cited evidence that probate
courts were motivated by foreign policy beliefs and anti-communist sentiment, which the Court held were
“matters for the Federal Government, not for local probate courts.” The law made judicial criticism of
foreign governments unavoidable, the Court reasoned, and therefore unconstitutionally intruded on the
federal government’s foreign affairs power.
Zschernig’s scope and continuing relevance is the subject of debate. The Supreme Court discussed the
case at length in its 2003 Garamendi opinion, but the Garamendi Court relied on traditional principles of
implied preemption rather than reinvigorating Zschernig’s “field of foreign affairs” concept. Still, the
Supreme Court has never overruled Zschernig directly, and the decision has ongoing validity as U.S.
courts of appeals continue to address and apply it.
Considerations for Congress
Congress has multiple avenues to influence and oversee states’ role in foreign affairs. As a result of
courts’ tapered interpretation of the congressional consent requirement in the Compact Clause, states
often conclude pacts with foreign governments without notifying Congress or seeking its approval. Some
Members of Congress have proposed improving transparency by requiring the Department of State to
track or maintain a database of subnational engagements. Congress could also consider legislation aimed
at requiring states to proactively seek its approval before concluding pacts. If Congress disapproves of
particular pacts or classes of pacts, it could consider legislation that seeks to preempt or restrict the state
action.
Some observers contend that the federal government should better integrate subnational governments in
the United States’ diplomatic efforts. The Biden Administration announced new initiatives designed to
foster engagement between U.S. cities and foreign countries. Some commentators and Members of
Congress have called for the Department of State to go further by creating a new office dedicated to
coordinating state and local foreign policy.
Congressional Research Service
5
Author Information
Stephen P. Mulligan
Legislative Attorney
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff
to congressional committees and Members of Congress. It operates solely at the behest of and under the direction of
Congress. Information in a CRS Report should not be relied upon for purposes other than public understanding of
information that has been provided by CRS to Members of Congress in connection with CRS’s institutional role.
CRS Reports, as a work of the United States Government, are not subject to copyright protection in the United
States. Any CRS Report may be reproduced and distributed in its entirety without permission from CRS. However,
as a CRS Report may include copyrighted images or material from a third party, you may need to obtain the
permission of the copyright holder if you wish to copy or otherwise use copyrighted material.
LSB10808 · VERSION 1 · NEW