Alfred T. Goodwin, Betty B. Fletcher, and Dorothy W. Nelson, Circuit Judges.
The opinion of the court was delivered by: D.w. Nelson, Circuit Judge
D.C. No. CR-92-00151-CAL, D.C. No. CR-93-00032-CAL, & D.C. No. CR-94-00086-1- MISC.
Appeals from the United States District Court for the Northern District of California Charles A. Legge, District Judge, Presiding
Argued and Submitted April 14, 1998--San Francisco, California
Opinion by Judge D.W. Nelson; Partial Concurrence and Partial Dissent by Judge Goodwin
Pol Brennan, Kevin Barry John Artt, and Terence Damien Kirby ("the appellants") appeal the district Judge's decision to certify them for extradition to the United Kingdom, pursuant to 18 U.S.C. S 3184 and the Extradition Treaty Between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland, June 8, 1972-Oct. 21, 1976, U.S.-U.K., 28 U.S.T. 227 (entered into force Jan. 21, 1977) (the "1977 Treaty"), as modified by the Supplementary Treaty Concerning the 1977 Treaty, June 25, 1985, U.S.-U.K., reprinted in S. Exec. Rep. No. 17, 99th Cong., 2d Sess., 15-17 (1986) ("Supplementary Treaty"). See Matter of Artt, 972 F. Supp. 1253 (N.D. Cal. 1997).
The appellants raise a number of defenses to extradition. They argue collectively that the extradition scheme established by Section 3184, the 1977 Treaty, and the Supplementary Treaty, unconstitutionally violates the doctrine of separation of powers and may not be used as a basis for their extradition. Alternatively, they claim that the district Judge misapplied the extradition treaties to their individual cases.
As we discuss below, our jurisdiction over this appeal arises in part from Article 3(b) of the Supplementary Treaty and in part from 28 U.S.C. S 1291. Although we commend the district Judge for his thoughtful and thorough Disposition of the issues raised by these cases, we conclude that he erred in applying the Supplementary Treaty to Appellant Brennan's case. We also conclude, with regard to the cases of Appellants Artt and Kirby, that the district Judge incorrectly defined the scope of inquiry under the first clause of Article 3(a) of the Supplementary Treaty. Accordingly, we reverse and remand for further proceedings in all three cases.
FACTUAL AND PROCEDURAL BACKGROUND
Beginning in 1973, the United Kingdom ("U.K.") enacted sweeping emergency legislation in its effort to stem the violence arising from the conflict in Northern Ireland. See generally Northern Ireland (Emergency Provisions) Act, 1978, ch.5 (consolidating emergency criminal provisions enacted between 1973 and 1978). This legislation eliminated a number of the pretrial procedural safeguards typically available to criminal defendants in Great Britain and Northern Ireland. See Note, Questions of Justice: U.S. Courts' Powers of Inquiry Under Article 3(a) of the United States-United Kingdom Supplementary Extradition Treaty, 62 Notre Dame L. Rev. 474, 479-81 (1987). It also established an alternative system of legal tribunals to try those accused of "scheduled offenses," i.e. certain politically-motivated criminal offenses. These "Diplock" courts, named after the chairman of the parliamentary commission that created them, employ abbreviated trial procedures, eliminating trial by jury and significantly relaxing evidentiary standards. See id. at 481-84; see also In the Matter of the Extradition of Smyth, 61 F.3d 711, 713 (9th Cir. 1995).
The appellants in the instant cases are Catholics from Northern Ireland. Each of them was convicted of criminal offenses by the Diplock court system. Pol Brennan was convicted in 1977 of possession of explosives with intent to endanger life or injure property and was sentenced to 16 years in prison. Terence Kirby was convicted in 1978 of possession of an explosive device, possession of a submachine gun, assault, false imprisonment, and felony murder, and was sentenced to life imprisonment. Barry Artt was convicted in 1983 of murdering a prison official and was sentenced to life imprisonment plus fifteen years.
In September 1983, all three escaped from the Maze Prison where they had been incarcerated, and made their way to the United States. When their identities were discovered, the U.K. requested their extradition pursuant to the 1977 Treaty. United States authorities arrested Artt in June 1992, Brennan in January 1993, and Kirby in February 1994.
After extensive discovery and a protracted bench trial, the district Judge certified the appellants for extradition. Matter of Artt, 972 F. Supp. 1253, 1274-75 (N.D. Cal. 1997). The Judge determined that the U.K. had met its burden under the 1977 Treaty of establishing that the appellants had been convicted of extraditable offenses in Northern Ireland. Id. at 1256. The Judge also concluded that the offenses of which all three appellants were convicted fell within the scope of the Supplementary Treaty and that, as a consequence, the appellants were barred from raising a defense to extradition under Article Five of the 1977 Treaty, which prohibits extradition for political offenses. Id. at 1260-62. Finally, the Judge concluded that none of the appellants had succeeded in establishing a defense to extradition under Article 3(a) of the Supplementary Treaty. Id. Brennan, Artt, and Kirby timely appeal.
The interpretation of treaties is a legal question subject to de novo review. United States v. Michael R., 90 F.3d 340, 343 (9th Cir. 1996). An extradition tribunal's factual determinations are reviewed for clear error. Oen Yin-Choy v. Robinson, 858 F.2d 1400, 1405 (9th Cir. 1988).
These cases present a number of issues of first impression. We consider, first, the appellants' challenge to the constitutionality of the extradition scheme which, they assert, violates the doctrine of separation of powers by exposing judicial decisions to executive branch review and by requiring Judges to act in an extra-judicial capacity. We also review the appellants' claim that the United States was a necessary party to the extradition proceedings on account of the unique role established for it by the Supplementary Treaty. We then proceed to the individual appellants' claims that the district Judge misconstrued various provisions of the Supplementary Treaty.
Before addressing these issues, however, we think it useful to review the extradition scheme governing our Disposition of this appeal.
The legal framework governing these appeals is defined by three legal instruments: Title 18 U.S.C. S 3184, the 1977 Treaty, and the Supplementary Treaty. Section 3184, the federal extradition statute, confers jurisdiction on "any Justice or Judge of the United States" or any authorized magistrate to conduct an extradition hearing pursuant to a treaty between the United States and another nation. 18 U.S.C.S 3184. The 1977 Treaty between the United States and the United Kingdom provides for the reciprocal extradition of persons accused or convicted of specified criminal offenses. The Supplementary Treaty, which is centrally at issue on this appeal, modifies the 1977 Treaty.
The United States and the United Kingdom adopted the Supplementary Treaty in 1985 in an effort to resolve increasing tensions arising from a series of extradition decisions by United States courts. See Smyth, 61 F.3d at 714. The Supplementary Treaty alters the extradition procedures in force under the 1977 Treaty in three significant ways: (1) it limits the scope of the political offense exception; (2) it authorizes a degree of judicial inquiry into the factors motivating a request for extradition; and (3) it creates a limited right to appeal an extradition decision. We discuss each of these changes in turn.
1. Article 1: Limits on the Political Offense Exception
Although judicial officers presiding over extradition proceedings typically refrain from " `inquir[ing] into the procedures or treatment which await a surrendered fugitive in the requesting country,' " Smyth, 61 F.3d at 714 (quoting Arnbjornsdottir-Mendler v. United States, 721 F.2d 679, 683 (9th Cir. 1983)), most extradition treaties contain an important exception to this rule, permitting a more probing judicial inquiry when the extraditee has been accused of a political crime. See generally Quinn v. Robinson, 783 F.2d 776, 792803 (9th Cir. 1986) (describing origins and application of political offense exception). The 1977 Treaty contains a typical formulation of this exception: It provides that extradition is not to be granted if "the offense for which extradition is requested is regarded by the requested party as one of a political character." 1977 Treaty, art. 5. Beginning in 1979, the political offense exception served as the basis for several decisions by United States courts to deny the extradition of members of the Provisional Irish Republican Army ("PIRA") to the United Kingdom. See Smyth, 61 F.3d at 714 (listing decisions). These decisions raised the ire of both the British government, which condemned the decisions as condoning terrorism, and the United States Departments of Justice and State, which feared that such decisions would have an adverse effect on law enforcement and foreign relations. Id.
The Supplementary Treaty was conceived as a means of limiting the scope of the political offense exception. See S. Exec. Rep. No. 99-17, at 1-2 (1986) ("Senate Report"). Article 1 of the Supplementary Treaty lists a number of specific criminal offenses that no longer may be "regarded as an offense of political character." Id. at 15. Among the crimes included on this list are murder, hostage-taking, and offenses "involving the use of a bomb . . . if this use endangers any person." Id. Also included are attempts to commit any of the listed crimes. Id. Article 1 of the Supplementary Treaty therefore makes the political offense exception inapplicable to most violent crimes.
2. Article 3(a): Limited Judicial Inquiry
As originally drafted, the Supplementary Treaty would have eliminated the political offense exception entirely. Senate Report at 3. Because of continuing concerns in the United States Senate about the fairness of the system of Justice in Northern Ireland, however, a unique provision was inserted to ensure that "American Judges have more than the usual authority to inquiry [sic] into that system, and to ensure that those we extradite will in fact get a fair trial. " 132 Cong. Rec. S16,806 (daily ed. July 14, 1986). Of particular concern to the Senate was the Diplock court system in Northern Ireland. See In re Extradition of Howard, 996 F.2d 1320, 1331 (1st Cir. 1993); see also 132 Cong. Rec. 16,806-19 (1986) (discussing procedures employed by Diplock courts).
 In its final form, the Supplementary Treaty contains the following provision: "Notwithstanding any other provision of this Supplementary treaty, extradition shall not occur if the person sought establishes to the satisfaction of the competent judicial authority by a preponderance of the evidence that the request for extradition has in fact been made with a view to try or punish him on account of his race, religion, nationality, or political opinions, or that he would, if surrendered, be prejudiced at his trial or punished, detained, or restricted in his personal liberty by reason of his race, religion, nationality, or political opinions."
Supplementary Treaty, Art. 3(a). Thus, while Article 1 of the Supplementary Treaty substantially curtails the application of the political offense exception, Article 3(a) authorizes extradition Judges to examine the factors motivating a request for extradition and, more broadly, "the treatment the accused will likely receive at the hands of the requesting country's criminal Justice system." Smyth, 61 F.3d at 715.
 In particular, Article 3(a) permits two distinct inquiries: The first clause of Article 3(a) authorizes the Judge to reject a request for extradition "based upon a persuasive factual showing that the requesting party has trumped-up charges against a dissident in order to obtain his extradition for trial or punishment." Senate Report at 4. The second clause gives the Judge the authority to deny extradition if the accused person can demonstrate "by a preponderance of the evidence that he would be prejudiced at his ...