The U.S. Foreign Sovereign Immunities Act of 1976 (the Act), which became effective on January 19, 1977, sought to codify the substantive law of sovereign immunity in the United States, while also modifying it in certain respects. An even more important goal was to make the application of such law more uniform, fair, and hence predictable, by relieving the Department of State of the responsibility to determine claims of such immunity, and remitting them exclusively to judicial determination, preferably in federal courts. Now, 2 years after it first took effect, it is appropriate to review the roughly two dozen cases that have applied and interpreted the Act, as well as certain questions that have otherwise arisen in practice, in order to ascertain whether (and, if so, where) significant uncertainties remain and amendment of the Act may be in order. Further, the taking effect of the new State Immunity Act 1978 in the United Kingdom on November 22, 1978, has provided an opportunity to see what others have learned from our experience. It also demonstrates the extent to which they have diverged from our design, suggesting the ultimate utility of a broad international convention on the subject.