(Five years after its enactment, the National Security Law has been increasingly integrated into Hong Kong’s legal system. The courts, through purposive interpretation and judicial restraint, have clarified its relationship with existing local laws while maintaining the common law traditions.)

The Hong Kong National Security Law (NSL) was enacted on June 30, 2020, and immediately incorporated into Annex III of the Basic Law by the Standing Committee of the National People’s Congress (NPCSC). It took effect in the HKSAR on the same day through promulgation. The NSL defines four categories of offences endangering national security but does not replace Hong Kong’s constitutional responsibility to legislate under Article 23 of the Basic Law. This obligation was reaffirmed in the National People’s Congress’s May 28 Decision in 2020. Following the enactment of the NSL, the Hong Kong Legislative Council passed the Safeguarding National Security Ordinance, which came into effect on March 23, 2024, fulfilling this long-standing duty nearly 27 years after Hong Kong’s reunification with China.

The NSL has fundamentally reshaped the city’s legal landscape. Much debate initially centred on its compatibility with Hong Kong’s common law tradition and judicial independence. Yet, Hong Kong’s courts have retained jurisdiction over national security cases, except in rare and exceptional circumstances specified under Article 55 of the NSL, which have not yet occurred. Over the past five years, the courts have handled a substantial number of national security cases, playing a pivotal role in restoring social order and ensuring the law’s effective enforcement. Hong Kong’s courts have gradually developed their own approach to applying the NSL. Through purposive interpretation and judicial restraint, the judiciary has integrated the law into the existing legal framework, clarifying its relationship with local statutes while preserving key elements of the common law system. This process offers a valuable case study in how national security laws can be reconciled with established legal traditions.

How Hong Kong Courts seeking the NSL’s Convergence, Compatibility and Complementarity with Local Laws

The NSL reflects distinct characteristics of the civil law tradition, integrating substantive criminal law, procedural law, institutional provisions, and administrative measures, with its offence definitions being more abstract than those in local criminal legislation. For Hong Kong’s courts, which operate within the common law tradition, correctly interpreting and applying the NSL presented a novel legal challenge. Hong Kong courts had previously established the purposive approach as an appropriate method of interpretation. This approach was further reinforced in the landmark Court of Final Appeal judgment concerning Lai Chee-Ying’s application for bail under NSL 42(2). The Court recognised that the NSL can be understood by referencing its text, the Basic Law, legislative materials, and official explanations issued during its enactment. The Court held that the legislative intention is for the NSL to operate in tandem with the laws of the HKSAR, seeking ‘convergence, compatibility and complementarity’ with local laws [and that] NSL 62 provides for possible inconsistencies, giving priority to NSL provisions in such cases.

First, Hong Kong courts emphasise the integration of the NSL into the local common law system. While the NSL was originally drafted with civil law characteristics, it has since been internalised as part of Hong Kong’s statutory framework, interpreted according to common law principles. The courts prefer to develop their own jurisprudence rather than directly borrowing from mainland legal interpretations. Where the NSL is silent or unchanged, pre-existing local laws, both procedural and substantive, continue to apply. 

Second, the courts recognise the NSL’s superiority over conflicting local laws, as provided under Article 62. In Lai Chee-Ying, the CFA overruled the recognition of the Court of First Instance in Tong Ying Kit, holding that NSL Article 42(2) creates a “particular exception” requiring stricter bail thresholds. Similarly, in Lui Sai Yu, the Court reaffirmed that while defendants are entitled to sentence reductions for guilty pleas, minimum sentencing thresholds under NSL Articles 20 and 21 are mandatory. Third, the purposive approach has fostered a preventive view of criminal law in national security cases, leading courts to impose deterrent sentences aimed not only at punishing offenders but also at protecting society from potential risks, as first articulated in Tong Ying Kit.

How Hong Kong Courts Establishing a State-centric Legal Framework regarding National Security

In applying the NSL, Hong Kong courts have demonstrated a form of "state-centric" understanding of national security. This holistic approach is, in part, the result of adopting purposive interpretation. First, the courts have developed a national security framework centred on the protection of Hong Kong’s constitutional order. The NSL provides a legal definition of “national security” that encompasses national sovereignty, constitutional order, and social stability, forming the legal basis for incorporating other relevant legal provisions into the broader national security framework. Second, the courts have recognised the open-ended nature of the national security regime, allowing the NSL’s procedural provisions to apply to other national security-related offences. For example, in Ng Hau Yi Sidney, the CFA’s Appeal Committee noted that Article 7 of the NSL requires Hong Kong to fulfil its obligation under Article 23 of the Basic Law, implying that the NSL does not exhaustively cover all national security offences. Thus, where the NSL refers broadly to “offences endangering national security” without further distinction, it should be interpreted to include both NSL offences and other national security-related offences under Hong Kong law. In this case, the offence of publishing seditious publications was treated as a national security offence, making the NSL bail regime applicable. 

Similarly, in Wong Kin-chung, although the defendant was charged with conspiracy, not an offence directly specified under the NSL, the Court of Appeal held that conspiracy to incite secession falls within the NSL’s sentencing framework, applying Article 21’s minimum sentences. In Cho Suet-sum Chloe, the District Court adopted a similar approach, ruling that defendants who conspired to publish seditious publications promoting Hong Kong independence committed offences closely resembling secession under the NSL, warranting deterrent sentencing consistent with Tong Ying Kit’s judgment.

In conclusion, as Hong Kong continues to navigate the complex interplay between national security and the rule of law, its courts have demonstrated how a national security regime can be integrated into a common law system while preserving core legal principles. Through purposive interpretation and judicial restraint, the judiciary has maintained both judicial independence and legal coherence in the face of politically sensitive cases. Beyond Hong Kong, this evolving jurisprudence offers a valuable reference point for other jurisdictions — particularly those operating within hybrid legal systems — that are seeking to reconcile national security imperatives with constitutional safeguards and international human rights norms. In an era where the boundaries between security and freedom are increasingly tested worldwide, Hong Kong’s experience may contribute important insights to the global discourse on balancing state sovereignty and fundamental rights under the rule of law.

Yang Xiaonan
Sun Yat-sen University, Law School, Professor of Law