Dual Criminality, Probable Cause, and the Limits of Habeas Review in U.S.–Japan Extradition: Commentary on Kanayama v. Kowal (2d Cir. 2025)

I. Introduction

The Second Circuit’s summary order in Kanayama v. Kowal, No. 24-1340-pr (2d Cir. Nov. 18, 2025), arises from an international extradition request by Japan under the 1978 Treaty on Extradition Between the United States of America and Japan (the “Treaty”). Although issued as a nonprecedential “summary order,” the decision provides a clear and tightly structured application of core doctrines governing extradition, especially:

The “dual criminality” requirement under Article II of the U.S.–Japan Extradition Treaty;
The highly limited scope of habeas corpus review of extradition certifications under 28 U.S.C. § 2241;
The low evidentiary threshold of probable cause in extradition proceedings and the “any evidence” standard on habeas review; and
The sharply constrained role of federal courts in considering humanitarian objections to extradition, which are reserved to the Secretary of State.

The case involves allegations that Masahide Kanayama traveled in Japan and surreptitiously applied oil to prominent religious sites—the Narita-san Shinsho-ji Temple and Katori Jingu Shrine—allegedly damaging these structures, in violation of Article 260 of the Japanese Penal Code (“damaging a building of another”). Japan sought his extradition from the United States; after an extradition hearing before Judge Edgardo Ramos and subsequent habeas corpus proceedings before Judge Colleen McMahon, the Secretary of State’s certification of extraditability was upheld. Kanayama then appealed to the Second Circuit.

The panel (Judges Lynch, Nardini, and Menashi) affirmed the denial of habeas relief, rejecting Kanayama’s arguments that:

His alleged conduct was not an “extraditable offense” within the meaning of the Treaty;
The evidence was insufficient to support a finding of probable cause; and
The lower courts erred in excluding defense evidence that would allegedly have “obliterated” Japan’s showing.

The opinion is especially instructive in its reiteration of:

The distinction between what is punishable under the laws of each country (the relevant Treaty standard) and what is actually prosecuted in practice;
The allocation of responsibilities between the judiciary and the executive (the Secretary of State) in extradition matters; and
The narrowness of habeas review in the extradition context, where courts do not conduct a mini-trial on guilt but merely ensure basic legal and evidentiary thresholds are met.

II. Factual and Procedural Background

A. Alleged Conduct in Japan

The underlying allegations trace to events on March 25, 2015, in Japan. Authorities claim that Kanayama damaged two religious sites—Narita-san Shinsho-ji Temple and Katori Jingu Shrine—by applying an “oily liquid” to them. This conduct led Japan’s Sakura Summary Court to issue two arrest warrants:

One on April 28, 2015
Another on December 8, 2015

Both warrants were for violations of Article 260 of the Japanese Penal Code, which criminalizes damaging a building of another and, as translated in the record, is punishable by up to five years’ imprisonment.

B. Japan’s Extradition Request and U.S. Proceedings

On December 12, 2016, Japan formally requested Kanayama’s extradition pursuant to the U.S.–Japan Extradition Treaty. The United States, acting on that request, filed a complaint under 18 U.S.C. § 3184 on May 30, 2017.

That same day:

Magistrate Judge Barbara C. Moses issued a warrant for Kanayama’s arrest.
He was arrested and presented before a magistrate judge.
He was released on bail pending extradition proceedings.

C. Extradition Certification Before Judge Ramos

On December 6, 2022, District Judge Edgardo Ramos (acting in his capacity as an “extradition judge” under § 3184) held an extradition hearing. On January 26, 2023, he certified to the Secretary of State that:

A valid Treaty existed between the United States and Japan;
The offenses for which Japan sought Kanayama were covered by the Treaty as extraditable offenses; and
There was probable cause to believe that Kanayama had committed those offenses.

D. Habeas Corpus Proceedings Before Judge McMahon

Kanayama challenged the certification by filing a habeas petition under 28 U.S.C. § 2241 in the Southern District of New York. On April 11, 2024, Judge Colleen McMahon denied the petition, holding that:

Judge Ramos had jurisdiction;
The offenses fell within the Treaty’s extraditable offense provisions; and
The record contained sufficient evidence to support a finding of probable cause under the applicable standard.

Judgment was entered April 12, 2024, and Kanayama filed a timely appeal.

E. Appeal to the Second Circuit

On appeal, Kanayama did not challenge Judge Ramos’s jurisdiction. His arguments focused instead on three points:

The alleged property damage offenses were not “encompassed by the Treaty” as extraditable offenses;
There was insufficient evidence to support probable cause to believe he committed the offenses; and
Both Judge Ramos (at the extradition stage) and Judge McMahon (on habeas) improperly excluded defense evidence related to these issues.

Additionally, in his appellate briefing he asserted—for the first time—that extradition would place him in a “life-threatening” situation given his health. The Second Circuit refused to entertain this late-raised humanitarian claim, both on forfeiture grounds and because, in any event, humanitarian determinations rest with the Secretary of State, not the courts.

III. Summary of the Second Circuit’s Decision

The Second Circuit affirmed the district court’s denial of habeas relief. The core holdings are:

Extraditable offense / dual criminality: The alleged conduct—damaging religious structures with oil—constitutes an “offense relating to the damage of property, documents, or facilities” under Schedule No. 19 of the Treaty and is “punishable by the laws of both Contracting Parties” by more than one year’s imprisonment. Japan’s Article 260 offense is punishable by up to five years; the U.S. counterpart is, at minimum, New York’s criminal mischief in the third degree (N.Y. Penal Law § 145.05), a Class E felony punishable by up to four years. The Treaty’s dual-criminality requirement thus is satisfied.
Probable cause: Under the very deferential standard applicable in habeas review of extradition certifications, the question is merely whether there is “any evidence” warranting the finding that there is reasonable ground to believe the accused guilty. The court held that Japan’s evidence—flight, rental, toll, and hotel records; surveillance video; expert identification comparing that video to Kanayama’s passport photo; YouTube videos in which he describes “anointing” shrines with oil; and repair and police reports documenting the damage—easily clears that low bar.
Exclusion of defense evidence: In extradition proceedings, a fugitive may introduce evidence only to “explain” the requesting country’s evidence, not to “contradict” it. Evidence that squarely contradicts the foreign state’s evidence is properly excluded. The panel held that the defense’s expert testimony (e.g., a woodwork expert disputing whether oil could penetrate lacquered surfaces; a facial recognition expert attacking the reliability of Japan’s identification report) was indeed contradictory, not explanatory. Therefore, both the extradition judge and the habeas court acted within their discretion in excluding it.
Humanitarian / health-based challenge: The argument that extradition would be “life-threatening” in light of Kanayama’s health was raised for the first time on appeal and thus was forfeited. The panel declined to review it under the discretionary “manifest injustice” exception. Moreover, it underscored that, even if timely raised, humanitarian objections go to the Secretary of State, not the courts, citing Lalama Gomez v. United States, 140 F.4th 49, 59 (2d Cir. 2025).

The court’s order is framed within long-standing limitations on judicial involvement in extradition, citing both Supreme Court and Second Circuit precedent.

IV. Detailed Analysis

A. Precedents on the Scope of Judicial Review in Extradition

The panel situates its analysis in a well-established doctrinal framework:

Cheung v. United States, 213 F.3d 82 (2d Cir. 2000): The extradition court (here, Judge Ramos) is permitted to consider only:
- whether a valid treaty exists;
- whether the crime charged is covered by that treaty; and
- whether the evidence is sufficient under the applicable standard of proof.
The panel directly quotes this three-part structure, reinforcing the limited nature of the extradition court’s inquiry.
Jhirad v. Ferrandina, 536 F.2d 478 (2d Cir. 1976): On habeas review of an extradition certification, the district court “can only inquire” into:
- whether the certifying court had jurisdiction;
- whether the offense charged falls within the treaty; and
- “by a somewhat liberal extension,” whether “there was any evidence warranting the finding that there was reasonable ground to believe the accused guilty.”
This articulation, in turn, guides the Second Circuit’s review of Judge McMahon’s habeas decision.
Murphy v. United States, 199 F.3d 599 (2d Cir. 1999): The panel emphasizes that the scope of appellate review of habeas denial in extradition cases is “narrow.” This aligns with the general principle that extradition is heavily constrained by treaty and statute, and courts are not to reweigh evidence or substitute their assessment of guilt.
Fernandez v. Phillips, 268 U.S. 311 (1925): The Supreme Court held that habeas corpus in extradition matters is available only to ask whether there was any evidence warranting the finding that there is reasonable ground to believe the accused guilty. The Second Circuit tracks this language, underscoring how deferential the federal courts must be in reviewing an extradition judge’s probable cause finding.
Melia v. United States, 667 F.2d 300 (2d Cir. 1981): The panel cites this case for the principle that the purpose of an extradition hearing is limited to determining whether “there is sufficient evidence to justify extradition under the appropriate treaty,” not to adjudicate guilt or innocence. This case supports the exclusion of contradictory defense evidence that would effectively transform the extradition hearing into a full-blown criminal trial.

Collectively, these precedents emphasize three themes:

Extradition is a treaty- and statute-driven process with tightly cabined judicial roles;
Habeas review of extradition decisions is even more limited than the extradition hearing itself; and
Federal courts must defer to the political branches (particularly the executive) on policy, diplomatic, and humanitarian considerations.

B. Dual Criminality and the “Extraditable Offense” Requirement

1. Treaty Structure and Article II

The Treaty’s Article II defines extraditable offenses in two main ways:

Enumerated offenses: Offenses listed in a schedule annexed to the Treaty and “punishable by the laws of both Contracting Parties” by more than one year’s deprivation of liberty.
Catchall clause: “Any other offense when such an offense is punishable by the federal laws of the United States and by the laws of Japan,” again with the requirement that the conduct be punishable by more than one year’s imprisonment.

Here, the panel mainly focuses on the first category, because Schedule No. 19 explicitly includes “[o]ffenses relating to the damage of property, documents, or facilities.” The court treats the alleged oil damage to temple and shrine structures as plainly fitting within this category.

2. Japanese Law and U.S. Law Counterparts

The court first looks to Japanese law:

Article 260 of the Japanese Penal Code, as translated in the record, states: “A person who damages a building or vessel of another shall be punished by imprisonment with work for not more than 5 years.”
Thus, the conduct is punishable in Japan by more than one year’s imprisonment.

On the U.S. side, the court looks to New York law (as the relevant jurisdiction where the fugitive is located):

N.Y. Penal Law § 145.05 (criminal mischief in the third degree):
- A person is guilty when, with intent to damage another person’s property, and having no right nor reasonable ground to believe they have such right, they damage property of another in an amount exceeding $250.
- Criminal mischief in the third degree is a Class E felony.
Penalty: Under N.Y. Penal Law § 70.00, a Class E felony is punishable by up to four years’ imprisonment—again, more than one year.

The court notes that Kanayama did not dispute that the maximum penalties under either Japanese or New York law exceed one year. Instead, he tried to argue that, in practice, his conduct would not have been prosecuted in New York.

3. “Punishable” vs. “Punished” – A Subtle but Important Distinction

The panel emphasizes a critical interpretive point:

“The operative question under the Treaty is not whether such conduct would have been punished under the laws of both countries, but whether it was punishable under both.”

This distinction matters. The Treaty does not inquire into prosecutorial discretion, local enforcement customs, or hypothetical likelihood of prosecution. It looks to:

Whether the laws of each country criminalize the conduct; and
Whether that conduct is legally punishable by more than a year of imprisonment.

At oral argument, Kanayama’s counsel conceded that he “could be charged” under New York law for this conduct. The panel treats that concession as effectively dispositive of dual criminality:

“That concession settles the dual criminality question.”

4. State Law as “Law of the United States” – Hu Yau-Leung and Wright v. Henkel

To support the use of New York Penal Law as the relevant U.S. counterpart, the court invokes two key precedents:

Hu Yau-Leung v. Soscia, 649 F.2d 914, 918 (2d Cir. 1981): The phrase “under the law of the United States of America” in an extradition treaty, referring to American criminal law, includes both state and federal law absent contrary evidence of intent.
Wright v. Henkel, 190 U.S. 40 (1903): The Supreme Court interpreted a U.S.–U.K. extradition treaty provision requiring that the offense be “made criminal by the laws of both countries” to encompass both state and federal law on the U.S. side.

By relying on these cases, the panel confirms that, for dual-criminality analysis under Article II’s first clause, it is entirely proper to look to state criminal statutes as the U.S. analogue to a foreign offense.

5. Footnote on the “Federal Laws” Clause

Both Judge Ramos and Judge McMahon had concluded that the conduct was extraditable under the second clause of Article II, which refers to offenses “punishable by the federal laws of the United States and by the laws of Japan.” The Second Circuit expressly avoids resolving that interpretive issue:

“Because Kanayama’s offenses fall cleanly within the scope of the first clause (which includes enumerated offenses punishable by the ‘laws’ of both the United States and Japan), we have no occasion to consider whether they also fall within the scope of the second clause, which requires that the fugitive’s offense be punishable under ‘federal laws of the United States.’”

Thus, the order:

Confirms that the first clause comfortably covers enumerated offenses punishable under both Japanese law and state or federal U.S. law; but
Leaves open how to interpret the second (“federal laws”) clause in circumstances where the offense is not on the Treaty’s enumerated list.

While not precedential, this structure suggests that future litigants seeking to rely on state-law analogues would be well advised to anchor their arguments in the first clause and its enumerated offenses where possible, avoiding the unresolved “federal laws” language in the second clause.

C. Probable Cause and the “Any Evidence” Standard on Habeas

1. The Probable Cause Standard in Extradition

The Second Circuit reiterates the classic extradition rule derived from Fernandez v. Phillips and other cases: the extradition court does not decide guilt or innocence. Its task is solely to determine whether there is “reasonable ground to believe” the accused guilty of the charged offenses—a probable cause standard comparable to that used for domestic arrest and bindover decisions.

On habeas review, this standard is further narrowed: the reviewing court asks only whether there was “any evidence warranting the finding” of reasonable ground to believe guilt. It does not conduct de novo review or reweigh the evidence.

2. Japan’s Evidentiary Showing

The record submitted by Japan (as summarized by the panel) included multiple strands of evidence:

Travel and location records: Flight, car rental, tollgate, and hotel records placing Kanayama in the vicinity of both the temple and shrine at the relevant dates and times.
Surveillance footage: Video showing a person resembling Kanayama touching the structures shortly before the damage was discovered.
Expert identification report: A comparison of the surveillance footage to Kanayama’s passport photograph, concluding that the individual in the footage matched him.
YouTube lectures: Videos in which Kanayama stated that he had previously “anointed” shrines with oil for religious reasons.
Repair estimates: Independent estimates documenting the damage and cost of repair to the affected structures at both sites.
Police reports: Investigation materials describing and measuring the damage.

The panel notes that this evidence “clears this low bar” of probable cause on habeas review.

3. Defendant’s Challenges and the Court’s Response

Kanayama challenged several elements:

Expert qualifications: He argued that Japan’s identification expert was not sufficiently qualified.
Relevance and timing of YouTube videos: He contended that the lectures, posted more than two years before the alleged offenses, did not prove intent or plan to commit the charged conduct.
Interpretation of toll records: He claimed that tollgate records merely showed he took the “fastest route” from the airport to his hotel and did not prove he visited the religious sites.

The panel disposes of these challenges by invoking a central principle of extradition law:

“[T]he credibility of witnesses and the weight to be accorded their testimony is solely within the province of the extraditing [] judge.”

Citing Lalama Gomez v. United States, 140 F.4th 49, 57 (2d Cir. 2025), the court underscores:

Such credibility and weight determinations are for the extradition judge (here, Judge Ramos), not for the habeas court or the appellate court.
Disputes about how strongly each piece of evidence points to guilt are classic trial questions—properly addressed in Japan’s criminal process, not in the U.S. extradition or habeas stages.

Thus, the existence of some evidence placing Kanayama near the scenes, some facial identification, some evidence of similar past conduct, and some objective documentation of damage sufficed for probable cause. The panel emphasizes that the threshold is “low” by design.

D. Limits on Defense Evidence: “Explaining” vs. “Contradicting”

1. The Governing Rule – Lalama Gomez

Extradition proceedings in the United States follow a unique evidentiary regime. The fugitive:

may introduce evidence that explains or clarifies the requesting state’s evidence; but
may not introduce evidence that merely contradicts the foreign government’s evidence or attempts to litigate guilt or innocence on the merits.

The panel cites Lalama Gomez for this rule, describing that the right to introduce evidence “is limited to testimony which explains rather than contradicts the demanding country’s proof,” and that the “precise scope of such explanatory evidence is largely in the discretion” of the extradition judge.

2. Application to Kanayama’s Proposed Evidence

Kanayama argued that the lower courts wrongfully excluded evidence that would have “obliterated” Japan’s showing of probable cause and an extraditable offense. According to his briefing (as summarized by the panel), he sought to introduce:

Woodwork expert testimony: To argue that vegetable oil could not have penetrated the lacquered surfaces of the wooden objects at Katori Shrine, contradicting Japan’s claim that oil caused the damage.
Facial recognition expert testimony: To critique Japan’s identification report as “fundamentally flawed” and “biased towards its conclusions.”

The panel characterizes this evidence as squarely contradicting—rather than explaining—Japan’s proof:

The woodwork expert did not clarify or contextualize Japan’s evidence, but instead offered an alternative narrative: the oil could not have caused the damage.
The facial recognition expert did not reconcile ambiguities; he attacked the methodology and validity of Japan’s identification evidence, essentially asking the U.S. court to affirmatively disbelieve Japan’s proof.

Because such evidence goes to the core of guilt and challenges the foreign state’s evidence head-on, it is considered inadmissible contradictory evidence in an extradition hearing. The panel thus concludes that Judge Ramos and Judge McMahon both acted well within their discretion in excluding it.

E. Forfeiture and Humanitarian Concerns

1. Forfeiture on Appeal – Windward Bora LLC v. Sotomayor

Kanayama argued on appeal that his extradition would put him in a “life-threatening” situation because of his health. However, this argument was not raised before Judge McMahon in the habeas petition. The panel, citing Windward Bora LLC v. Sotomayor, 113 F.4th 236, 245 (2d Cir. 2024), treats the argument as forfeited, noting:

The Second Circuit has discretion to consider forfeited arguments in “manifest injustice” cases; but
The panel “discern[s] no need” to do so here.

2. Humanitarian Issues Reserved to the Secretary of State – Lalama Gomez

Even if the argument had been properly raised below, the panel emphasizes that humanitarian concerns—such as health risks or prison conditions—are for the Secretary of State to weigh, not the courts. Quoting Lalama Gomez:

“[I]t is the function of the Secretary of State—not the courts—to determine whether extradition should be denied on humanitarian grounds.”

This principle reflects the separation-of-powers structure of extradition:

Courts assess only narrow, legally defined questions about treaty applicability, jurisdiction, and probable cause.
The executive branch, acting through the Secretary of State, weighs diplomatic, foreign policy, and humanitarian considerations in determining whether to surrender the fugitive.

V. Clarifying Key Legal Concepts

A. Extradition and the Role of § 3184

Under 18 U.S.C. § 3184, when a foreign state requests extradition under a treaty:

A complaint is filed in a U.S. district court;
A judge (or magistrate) issues a warrant and holds a hearing;
If the judge finds that the evidence is sufficient and the offense is extraditable, the judge “certifies” the case to the Secretary of State;
The Secretary of State then decides whether to surrender the person to the foreign authorities.

The extradition judge does not order extradition. Instead, the judge certifies that legal conditions are met, leaving the final diplomatic decision to the executive.

B. Dual Criminality

“Dual criminality” means that:

The conduct underlying the foreign charges must be criminal under the laws of both the requesting and requested states; and
The conduct must be punishable (not necessarily actually punished) with a certain minimum severity—here, more than one year’s deprivation of liberty.

It does not require that:

The two legal systems have identical statutes or labels;
The elements line up perfectly; or
The foreign law track verbatim the text of the domestic law.

Rather, courts ask whether the essential conduct would be criminal in both jurisdictions.

C. “Punishable” vs. “Punished”

The Treaty’s language focuses on crimes “punishable” by certain penalties. This is an important distinction:

Punishable: The law authorizes specified penalties (e.g., up to four years in prison) for the offense.
Punished: In practice, how prosecutors and courts typically treat such cases (e.g., diversion, fines, or lenient sentencing).

In Treaty interpretation, courts look to whether the conduct could lawfully be charged and punished as a crime with the requisite penalty, not whether local prosecutors would likely exercise discretion to forego prosecution.

D. Habeas Corpus in Extradition: The “Any Evidence” Test

Under 28 U.S.C. § 2241, habeas corpus is available to challenge extradition certifications, but in a highly limited way. The habeas court asks:

Did the extradition court have jurisdiction?
Is the charged offense within the scope of the treaty?
Is there any evidence supporting a finding of probable cause (i.e., reasonable ground to believe the accused guilty)?

The court does not:

Weigh competing testimony or assess credibility;
Resolve factual disputes as a jury would;
Adjudicate affirmative defenses (e.g., alibi, mistaken identity) that contradict the foreign state’s narrative.

E. Explanatory vs. Contradictory Evidence

A persistent source of confusion in extradition litigation is the distinction between:

Explanatory evidence: Evidence that clarifies, supplements, or puts into context the requesting state’s evidence without directly contradicting it—for example, clarification of ambiguous documents or translations.
Contradictory evidence: Evidence that seeks to negate or discredit the foreign evidence—for example, alibi testimony, expert critiques designed to show that the foreign identification is unreliable, or alternate theories of causation for the damage.

Only explanatory evidence is admissible in an extradition hearing. Contradictory evidence is generally excluded because allowing it would effectively convert the extradition process into a full criminal trial, undermining the Treaty’s allocation of criminal adjudication to the requesting state.

F. Summary Orders and Precedential Effect

The court opens with a standard notice that this is a summary order:

Summary orders filed on or after January 1, 2007, may be cited under Federal Rule of Appellate Procedure 32.1 and the Second Circuit’s Local Rule 32.1.1.
However, they have no precedential effect. They may be considered persuasive but do not bind future panels.
Parties citing a summary order must note that it is a “SUMMARY ORDER” and serve a copy on any unrepresented party.

Thus, while Kanayama v. Kowal does not create binding law, its reasoning, grounded in precedential authorities like Fernandez, Hu Yau-Leung, Jhirad, and Lalama Gomez, is a useful window into how the Second Circuit currently applies established extradition principles.

VI. Practical Impact and Broader Significance

A. For Defense Counsel in Extradition Cases

The decision carries practical lessons for defense lawyers:

Frame challenges within the narrow permissible scope: Attacks on the quality or weight of the foreign evidence (e.g., expert critiques of identification, alternative damage theories) will largely be treated as impermissible contradictions.
Focus on legal defects: If there is any viable argument that:
- no valid treaty exists;
- the offense is not within the Treaty; or
- there is truly no evidence connecting the client to the offense (as opposed to weak evidence),
those arguments have a better chance of gaining traction.
Raise all arguments in the extradition and habeas courts: As Windward Bora and this case demonstrate, arguments not presented below, especially humanitarian and constitutional claims, risk being deemed forfeited on appeal.
Recognize where to take humanitarian concerns: Health risks, prison conditions, or other humanitarian grounds should be primarily addressed to the Secretary of State, not the courts. Judicial resources may be better spent creating a robust record for the State Department’s consideration.

B. For Prosecutors and Foreign States

For the United States and requesting states (like Japan), the case confirms that:

Document-based evidence travels well: Travel records, surveillance video, official reports, and even publicly available online statements (like YouTube lectures) can cumulatively suffice for probable cause in extradition.
Enumerated Treaty offenses are powerful: Aligning the foreign charges with an enumerated Treaty offense (here, “relating to the damage of property”) simplifies dual-criminality analysis and avoids harder interpretive questions about catchall clauses.
State law analogues are acceptable: Where the Treaty references “laws” of the United States, state criminal laws are valid comparators, consistent with Hu Yau-Leung and Wright.

C. For the Development of Extradition Law

In the broader doctrinal landscape, Kanayama:

Reaffirms established doctrines on dual criminality, the narrow scope of habeas review, and the explanatory vs. contradictory evidence distinction.
Illustrates how newer Second Circuit authority such as Lalama Gomez integrates with older Supreme Court and circuit precedents, particularly in assigning humanitarian questions to the Secretary of State.
Leaves unresolved the precise scope of Treaty clauses requiring that offenses be punishable by “federal laws of the United States,” signaling that future litigants may see further development there in published opinions.

D. Policy and Separation-of-Powers Considerations

The opinion, consistent with extradition jurisprudence generally, reflects a broader policy choice:

Judicial roles are limited: Courts address legal thresholds and basic evidentiary sufficiency but avoid encroaching on foreign policy, diplomacy, and humanitarian balancing.
Executive primacy in extradition: The Secretary of State, as an executive official, bears responsibility for weighing diplomatic relations, humanitarian conditions, and foreign policy before authorizing surrender.

This separation-of-powers approach:

Prevents courts from becoming forums for relitigating foreign criminal cases;
Maintains comity with foreign judicial systems; and
Preserves the constitutional allocation of foreign affairs functions to the political branches.

VII. Conclusion

Kanayama v. Kowal is a nonprecedential Second Circuit summary order, but it presents a textbook application of core U.S. extradition principles in the context of the U.S.–Japan Extradition Treaty. It:

Confirms that damaging religious structures with oil falls squarely under the Treaty’s enumerated offenses “relating to the damage of property, documents, or facilities,” satisfying dual criminality when an analogous state offense (New York’s criminal mischief in the third degree) is punishable by more than one year.
Reiterates that the relevant Treaty inquiry is whether conduct is punishable by law in both countries, not whether it would necessarily be prosecuted.
Reaffirms the extremely limited nature of habeas review in extradition matters—courts ask only whether there is “any evidence” supporting a probable cause finding and do not weigh credibility or resolve evidentiary disputes.
Clarifies, once again, that defense evidence in extradition must be explanatory, not contradictory; expert testimony aimed at undermining the foreign state’s evidence on causation or identification is properly excluded.
Emphasizes that humanitarian objections to extradition (such as serious health risks) are the province of the Secretary of State, not the judiciary, and must be timely raised if they are to be considered in any form.

For practitioners, the order serves as a practical reminder of the structural constraints around extradition litigation. For scholars and judges, it illustrates the continuing vitality of long-standing extradition doctrine—Fernandez, Wright, Hu Yau-Leung, Jhirad, Melia—as filtered through more recent Second Circuit authority like Lalama Gomez.

While not binding precedent, Kanayama is a clear and faithful application of that body of law to a contemporary extradition dispute, underscoring that challenges to treaty coverage and evidentiary sufficiency in extradition cases face an intentionally high bar in federal court.