## Facts

- William A. Parker conducted a typewriter and office-supplies business in Mexico City from about December 1911 through March 27, 1918, and then formed a Mexican corporation, Compañía Parker S.A., to continue the business.
- Parker (through his business) supplied goods and repair services to various Mexican government departments at agreed prices.
- After crediting payments, Parker claimed Mexico still owed about $39,090 for delivered goods and services.
- The United States presented the claim on Parker’s behalf under the United States–Mexico General Claims Convention (1923).
- Mexico objected that Parker’s American nationality was not adequately proved, criticizing reliance on Parker’s testimony and affidavits from his brother and a long-time friend, and arguing that affidavits taken before a U.S. vice-consul lacked validity under Mexican law.
- A prior Mexican motion to dismiss was denied; the decision addressed nationality proof and evidentiary standards as a preliminary matter rather than the merits of the debt claim.

## Issues

1. Whether espousal of a claim by the United States creates a presumption that the private claimant is a U.S. national for purposes of an international claim.
2. Whether Parker’s testimony and supporting affidavits, without a birth certificate, sufficiently established his American nationality.
3. Whether the Commission was bound by municipal evidentiary rules (including Mexican rules concerning consular authority) when deciding admissibility and weight of affidavits and other documents.
4. Whether, after a prima facie showing of nationality and absent rebuttal evidence, Mexico could demand additional proof at a higher standard.

## Decision

- The Commission held that espousal alone does not create any presumption that the claimant has the espousing state’s nationality.
- The Commission ruled that nationality is a fact that must be proved to the tribunal’s satisfaction, like any other material fact.
- The Commission admitted the proffered affidavits and related materials under a liberal evidentiary approach and found them sufficient, in the absence of rebuttal, to establish Parker’s American nationality.
- The Commission stated it was not bound by municipal rules of evidence and would apply broad liberality in admitting proof.
- The claim was permitted to proceed on the basis that nationality had been adequately established, leaving the monetary merits for later determination.

## Legal Principles

- Espousal of a private claim by a state does not, by itself, prove or presumptively establish the claimant’s nationality.
- Nationality in international claims is a factual matter requiring proof to the tribunal’s satisfaction.
- International claims tribunals may admit evidence under flexible standards and are not constrained by domestic evidentiary rules; admissibility and weight are distinct determinations for the tribunal.
- Where a claimant presents prima facie evidence on a jurisdictional fact (such as nationality) and the respondent produces no rebuttal evidence, the respondent cannot insist on exhaustive additional proof as a condition to moving forward.
- Agents of both governments bear a duty to cooperate in presenting reasonably ascertainable relevant facts to the tribunal.

## Conclusion

The Commission rejected any presumption of nationality based on espousal, required affirmative proof of nationality as a factual element, and applied liberal evidentiary standards to accept unrebutted affidavits and testimony as sufficient to establish nationality and allow the claim to proceed.


Parker (U.S.A.) v. United Mexican States, 4 R.I.A.A. 35 (Gen. Cl. Comm’n U.S.-Mex. 1926)