Foreign law expert
Expert class library · International arbitration · Either side
A foreign lawyer, judge or law professor who explains the content of another country's law to a U.S. court or tribunal: what a statute or code provision means, how foreign courts apply it, and what documents prove a right under it. Because U.S. courts treat foreign law as a question of law, not fact, the judge may consider any relevant source and is not bound by either side's expert, so the fights are less about Daubert and more about timing, weight and deference. Courts exclude foreign law evidence raised too late, weigh experts against a foreign government's own statements, and rely on expert declarations even at the pleading stage.
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What this expert is retained to answer
- Was notice of the foreign law issue given in time, as Rule 44.1 requires, or raised for the first time at summary judgment?
- Does the expert explain the content of the foreign law, or apply it to the facts and argue the outcome?
- Is the expert's account supported by statutes, cases and commentary the court can check?
- How does the opinion square with any statement the foreign government has made about its own law?
- Does the foreign law recognize informal customs, or only formal documents and procedures?
Methods
- Analysis of foreign statutes, codes and regulations
- Review of foreign case law and legal commentary
- Explanation of foreign legal procedure and practice
- Translation and interpretation of legal terms
- Comparison of foreign law with U.S. legal concepts
How the testimony is attacked
- Raised too late. Foreign law raised at the last minute can be excluded. In Azarax v. Syverson the Eighth Circuit upheld excluding a law professor's affidavit on Mexican corporate law offered for the first time in opposition to summary judgment after three years of litigation.
- Contrary to the foreign government's view. A foreign government's statement about its own law deserves respectful consideration but is not conclusive. In Animal Science Products v. Hebei Welcome Pharmaceutical the Supreme Court held courts may weigh such a statement against expert testimony and other evidence.
- Conversion to summary judgment. Opponents argue that relying on a foreign law expert's declaration turns a motion to dismiss into summary judgment. In Sharifi v. United States the Federal Circuit held it does not, because determining foreign law is a ruling on a question of law.
- Applying the law to the facts. Foreign law experts are meant to explain the content of the law. Opinions that apply it to the facts of the case and argue the result are given little weight.
- Unsupported assertions. Courts discount expert accounts of foreign law that do not cite statutes, cases or commentary the court can verify.
What the public record shows
Courts have filed at least 23 opinions since 2015 that address this class of testimony under Daubert or Rule 702, as of October 4, 2026. Three that show how courts handle this class of testimony:
| Outcome | Case | Court | Year | Why |
|---|---|---|---|---|
| Excluded | Azarax, Inc. v. Syverson990 F.3d 648 | 8th Cir. | 2021 | The Eighth Circuit held the district court did not abuse its discretion by excluding evidence of Mexican corporate law, including a law professor's affidavit, that the plaintiff raised for the first time in response to summary judgment after more than three years of litigation without justifying the late notice, and affirmed dismissal for lack of standing. |
| Admitted | Sharifi v. United States987 F.3d 1063 | Fed. Cir. | 2021 | Affirming dismissal of a takings claim over land in Afghanistan, the Federal Circuit held the Claims Court properly relied on the government's expert declaration on Afghan law, together with its own research, to decide what documents prove land ownership, and that doing so under Rule 44.1 did not convert the motion to dismiss into one for summary judgment. |
| Sent back for review | Animal Science Products, Inc. v. Hebei Welcome Pharmaceutical Co.585 U.S. 33 | U.S. | 2018 | In a price-fixing case where the parties offered competing expert testimony on Chinese law, the Supreme Court unanimously vacated a decision treating the Chinese ministry's statement of its law as binding, holding that federal courts should give a foreign government's statement respectful consideration but are not bound by it and may consider any relevant material. |
Each case links to the free opinion text on CourtListener.
Under amended Rule 702
Since December 1, 2023, Rule 702 says expressly that the party offering an expert must show the court it is more likely than not that the testimony meets each requirement: that it rests on sufficient facts or data, uses reliable methods, and reflects a reliable application of those methods to the case. Questions about the basis of an opinion are no longer automatically matters of weight for the jury. For how the circuits have applied the amendment, see the Rule 702 tracker, which follows each court of appeals; for what that means for preparing or attacking this class of expert, see the guide on amended Rule 702.
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Last reviewed October 4, 2026. How this page is built: rulings are found by searching court opinions on CourtListener, and each one is read in the opinion before it is summarised here; outcomes are labelled by what the court did with the expert's testimony. No individual expert is named. This page summarises public decisions for orientation and is not legal advice; read the opinion before relying on any ruling.