The recent enactment of a subsidiary legislation in Hong Kong regarding the appropriate procedure to be followed in cases of non-national security offences involving national security considerations not surprisingly spurred some to revisit the chief executive’s power, granted under the national security law in 2020, to issue a certificate as to whether an act involves issues of national security.

That some people express concern that such an important task is left to the executive and not the judiciary is understandable only because they have failed to understand the governing rationale behind this distinction.

Many common law jurisdictions accept that the court is not an appropriate forum to determine matters of national security. Note that I am referring to national security issues and NOT national security offences. There is a vital difference.

In the United States, this difference has been recognised and accepted for decades. Supreme Court cases from Navy vs Egan (1988) to Holder vs Humanitarian Law Project (2010) to the most recent case of FBI vs Fazaga (2022) have confirmed repeatedly that national security risk assessments fall within the exclusive competence of the executive branch because they require predictive judgments based on sensitive intelligence.

Courts may not second-guess these determinations as they lack the necessary institutional competence to evaluate sensitive intelligence or threat assessments. It follows that there is a clear and necessary distinction between executive national security determinations and the judicial adjudication of national security crimes.

The position in Britain is no different. In the landmark case of Secretary of State for the Home Department vs Rehman (2001), the House of Lords, then Britain’s highest court, reaffirmed the principle that identifying a threat to national security is an executive function, not a judicial one, and that the courts cannot substitute their own assessment of national security risk for that of the home secretary’s.