The decision includes articles authorising national security organs of the central government to establish branches in Hong Kong (most likely the Ministry of State Security) and an article authorising the NPC Standing Committee (NPCSC) to draft a new national security law to be implemented in the city. The specifics of this law are still vague, but they will touch on four areas — secession, subversion of state power, terrorist activities and ‘activities by foreign and overseas forces that interfere in the affairs’ of Hong Kong.

Two things are clear: the NPC decision is almost certainly unconstitutional with regards to Hong Kong law and neither Beijing nor the pro-Beijing political establishment in Hong Kong care much about its legality.

In a rhetorical manoeuvre similar to the frequent repetition of the Chinese Communist Party’s ‘core socialist values’, both Beijing and the Hong Kong government have doubled down on invoking One Country, Two Systems (1C2S). The decision to impose national security law is in fact an ‘improvement’ on 1C2S — a way to ‘ensure the enduring success’ of the framework, according to official statements.

Yet if 1C2S means anything, it is the separation of the political systems of Hong Kong and the mainland, guaranteeing judicial independence and legislative autonomy in the Special Administrative Region — the exact autonomy which the current decision is set to undermine. While 1C2S is certain to remain a favoured phrase of the establishment, the principle itself — and the rights and freedoms it was meant to guarantee — seem entirely dead, spelling the end of an era for Hong Kong.

What makes the NPC decision unconstitutional? As it currently stands, the Basic Law — Hong Kong’s constitutional document — clearly sets out that the local legislature has the responsibility to ‘enact laws on its own to prohibit any act of treason, secession, sedition, subversion…’ This is covered in Article 23.

Beijing is currently proposing to implement national security law in Hong Kong, drafted by the NPCSC, via Article 18. Article 18 makes clear that national (meaning PRC) laws shall not be applied in Hong Kong, with the exception of a set of laws listed in Annex III. These laws ‘shall be confined to those relating to defense and foreign affairs as well as other matters outside the limits of the autonomy of the Region…’

The implementation of the laws added to Annex III can take place either via promulgation — meaning that the Hong Kong Chief Executive issues a legal notice and enacts the law — or via legislation, meaning that the laws have to go through the Legislative Council (LegCo) and be made into legislation appropriate to Hong Kong’s existing legal system.

By imposing national security law in Hong Kong via Annex III, Beijing is planning to go the promulgation route and implement the law very quickly, without consulting LegCo or any other local institution. This would most certainly go against established practice. But promulgation would not necessarily be against Hong Kong constitutional law.

What does appear unconstitutional is using Article 18, rather than Article 23, to implement national security law. The areas that the proposed law touch on are explicitly covered under Article 23. These are two different articles for a reason — subversion and secession do not equate to foreign and defence affairs, as currently defined in the Basic Law.

Given that Annex III only applies to laws that fall outside the limits of Hong Kong autonomy, and that this emphatically does not include issues of national security, Beijing’s move is on its face unconstitutional. It seeks to bypass existing legislative channels and reinterpret the very meaning of autonomy.

The power of final interpretation of the Basic Law lies with the NPCSC, so what is at present an unconstitutional move could swiftly be turned into legal fact by the Beijing body’s reinterpretation (or more accurately rewriting) of Articles 18 and 23. Such a move would be possible given the powers granted to the NPC, but it would also be the final nail in the coffin of Hong Kong’s legislative autonomy, going against the promises made in the Sino-British Joint Declaration more than three decades ago.

Beyond the issues of constitutionality lie more immediate concerns over the consequences of the national security law. New draconian laws on secession, subversion and the interference of foreign entities in Hong Kong would likely criminalise a host of activities that are currently common practice, and which are in fact protected as rights by the Basic Law (Article 27). Freedom of assembly, freedom of speech and freedom of association are sure to be heavily curtailed. Former Hong Kong chief executive C Y Leung said as much over the weekend, hinting in an interview that vigils commemorating the Tiananmen Square Massacre are likely to be outlawed in Hong Kong going forward.

Nobody knows exactly what will come next, but one thing seems certain. While the end of Hong Kong’s autonomy is upon us, the city is not ready to go silently into the night. Large-scale protests erupted over the weekend, after months of quiet during the pandemic, and more are sure to follow over the coming weeks.

Dr Jeppe Mulich is a teaching associate of global history at the Faculty of History, The University of Cambridge.