In late 2018, the American Law Institute released a volume of the Restatement Fourth of the Foreign Relations Law of the United States. Initiated in October 2012 under the direction of Coordinating Reporters Sarah Cleveland and Paul Stephan, this volume covers three areas of U.S. foreign relations law: treaties, jurisdiction, and sovereign immunity. It remains to be seen whether the American Law Institute will revisit other portions of the Restatement Third, which was published in 1987.Footnote ¹ “[I]n the meantime, the provisions of the Third Restatement remain the position of The American Law Institute except where superseded by provisions in this Fourth Restatement.”Footnote ²

The Restatement Fourth's section on treaties was led by Reporters Curtis Bradley, Sarah Cleveland, and Edward Swaine. This section covers only treaties joined through the domestic legal process specified in the U.S. Constitution's Treaty Clause and does not discuss other types of international agreements made by the United States.Footnote ³ There are several notable changes from the Restatement Third. Among them is that the comments to Section 306 on the interpretation of treaties acknowledge that Articles 31 and 32 of the Vienna Convention on the Law of Treaties are now regarded as reflective of customary international law, including by the United States.Footnote ⁴ Another change is that Section 310, although “generally consistent with the approach of the Restatement Third,” substantially updates the Restatement Third's language regarding the self-execution of treaties to account for the U.S. Supreme Court's decision in Medellín v. TexasFootnote ⁵ and other developments subsequent to the Restatement Third's publication.Footnote ⁶ A third difference is that, “[u]nlike in the prior two Restatements, [the Restatement Fourth] does not take a position on whether there is some sort of subject-matter limitation on the treaty power.”Footnote ⁷

The Restatement Fourth's section on jurisdiction was led by Reporters William Dodge, Anthea Roberts, and Paul Stephan. In contrast to the Restatement Third, the Restatement Fourth's section on jurisdiction generally places more emphasis on domestic law.Footnote ⁸ In an important specific difference, Section 407 of the Restatement Fourth does not retain the former Section 403's insistence that, under international law, exercises of prescriptive jurisdiction must be “reasonable” as determined by various factors.Footnote ⁹ Instead, the Restatement Fourth replaces the reasonableness requirement, which was “not supported by state practice,” with the requirement that a “genuine connection” exist “between the subject of the regulation and the state seeking to regulate.”Footnote ¹⁰ The Restatement Fourth nevertheless retains the bases for prescriptive jurisdiction provided for in Sections 402 and 404 of the Restatement Third.Footnote ¹¹ Section 405 of the Restatement Fourth separately recognizes that, as a matter of “prescriptive comity,” courts in the United States may apply a principle of reasonableness in interpreting federal statutes, although this principle does not entitle courts to decline to apply federal law.Footnote ¹² The Restatement Fourth also includes a section on the presumption against extraterritoriality, which was included in the Restatement Second but not the Restatement Third.Footnote ¹³

The Restatement Fourth's section on sovereign immunity was led by Reporters David Stewart and Ingrid Wuerth. Among other notable changes, Section 456 of the Restatement Fourth substantially revises Section 455(1) of the Restatement Third concerning claims to property.Footnote ¹⁴ In particular, Section 456 omits the provision concerning the types of claims to which states as a general matter are not immune from jurisdiction under international law.Footnote ¹⁵ Instead, it discusses only the types of claims to property over which courts in the United States may exercise jurisdiction.Footnote ¹⁶ Additionally, the Restatement Fourth includes a new section providing that foreign states are not immune from suit in U.S. courts in actions to compel arbitration pursuant to an agreement to arbitrate, reflecting the adoption in 1988 of Section 1605(a)(6) of the Foreign Sovereign Immunities Act (FSIA).Footnote ¹⁷ The Restatement Fourth also includes a new section on claims against state sponsors of terrorism to account for various legislative enactments adopted through the period from 1996 to 2016.Footnote ¹⁸ These include Section 1605A of the FSIA, which provides for a terrorism exception to foreign states’ immunity from jurisdiction, as well as the Justice Against Sponsors of Terrorism Act.Footnote ¹⁹