The legal fight over Daniel Duggan, a former U.S. Marine who was arrested in the United Kingdom last year on an American extradition request, resumed this week as his lawyers asked a British court to block transfer to the United States. U.S. prosecutors allege Duggan provided aviation instruction to Chinese military pilots, conduct they say violated U.S. laws governing military assistance and export controls. Duggan has denied wrongdoing through his legal team, which says he worked as a civilian instructor and that the allegations do not amount to an extraditable offense.

"The claims stem from lawful civilian aviation training and are at odds with the facts," a lawyer for Duggan told reporters, reiterating arguments submitted in the appeal. The U.S. Justice Department, citing national security concerns, has maintained that the alleged activities amounted to material support to a foreign military and therefore fall squarely within U.S. jurisdiction. Court filings reviewed by AP describe instruction at aviation facilities in China, but the defense has challenged the characterization and the evidentiary basis for the extradition request.

The dispute turns on legal standards in the U.S.-U.K. extradition framework, including the requirement of dual criminality — that the conduct be an offence in both countries — and whether the request is politically motivated or disproportionate. The 2003 treaty that governs most bilateral extraditions allows the United States to seek transfer for a wide range of crimes, but British judges retain discretion to refuse in cases where human rights, political offences or other defenses apply.

Beyond the courtroom, the case is emblematic of a broader policy shift in Washington toward aggressive enforcement of export controls and sanctions aimed at preventing the transfer of specialized skills and technology to China. U.S. officials have tightened rules in recent years on everything from semiconductors to advanced avionics; defendants accused of aiding foreign militaries can face decades in prison if convicted. That enforcement stance is part of a larger strategic competition: the United States spends roughly $800 billion a year on defense — about 3 to 4 percent of GDP — while China’s official defense budget has crossed the $200 billion mark, underscoring why U.S. policymakers are sensitive to any training that could improve Beijing’s military capabilities.

Market participants and industry groups are watching closely. Legal uncertainty and the prospect of stricter oversight could raise compliance costs for private aviation firms and contractors that operate globally, even as defense contractors and governments continue to benefit from elevated defense budgets. Analysts say that if courts broadly endorse extraterritorial enforcement, companies that provide technical training abroad may face more onerous due diligence obligations and potential reputational risk.

A ruling granting extradition would reinforce U.S. reach in national security prosecutions and likely prompt closer scrutiny of U.S. veterans and contractors working overseas. A refusal would bolster arguments for narrower interpretation of extraterritorial jurisdiction and could temper Washington’s enforcement ambitions. For Duggan, the legal and personal stakes are high: the outcome will not only determine whether he faces trial in the United States, but could also set a precedent with implications for transnational training, international aviation services and the limits of U.S. export‑control law.