More importantly, their legal philosophies could not be more different. But in their profound opposition, they encapsulate the very dilemma of Hong Kong as it has been at war with itself and with the rest of the country. In trying to figure the way forward, or a way out, for the city, both legal scholars resort to advocating measures and actions that go beyond the law and constitution.

Chen counsels intervention from above, by the state, to restore order, stability and governability, the very preconditions for the law itself to function. Tai advocates fighting from below, by the people, and committing violence if necessary, to bring about desired change.

Most Hong Kong people likely fall into the one or the other camp. Alternatively, you may think of their opposition as exemplifying a process of action and reaction between Hong Kong and Beijing – an endless downward spiral, through countless misunderstanding, miscalculations and bad intentions – that is ruining the city today.

Let’s start with Chen and his keynote speech. Chen cited Thomas Hobbes in arguing that anything the sovereign does is right and legal in the name of state security. This is because without security, the law cannot function or even exist. Hence Hobbes’ oft-quoted statement: “Covenants, without the sword, are but words, and of no strength to secure a man at all.”

This is one of the key arguments of Hobbes’ Leviathan, which for Chen provides a convenient justification against the common Western-democratic criticism that the Chinese Communist one-party state frequently appears to breach the written national constitution.

Not all constitutions are written down. For example, Britain doesn’t have one. The “real” and by far more important constitution of any state, written or not, must secure its own safety and that of its citizens. That falls under the general heading of “national security”. If a written constitution fails to provide national security, or worse, if it is being used to subvert national security, the “real” constitution kicks in.

“The constitution is the law of national self-preservation, not a ‘suicide pact’,” Chen said. “On the one hand, the constitutional system must be designed with the fundamental purpose of safeguarding national security; and on the other, in the process of implementation, it cannot be interpreted in ways that go against this fundamental purpose, namely, endangering national security.”

We can see where he is taking us. Hong Kong has been caught in this “suicide pact” as pro-democracy legal scholars and anti-government activists have interpreted the Basic Law in precisely such a dangerous way – and then carried out more than half a year of laam chau.

“When some Western countries and Hong Kong’s laam chau movement attacked Hong Kong’s national security law, in conceptual terms, they separated the validity and vitality of the Hong Kong Basic Law from Chinese sovereignty, and even set up the two as antagonistic. This is poor reasoning, and the essence of it is Hong Kong independence,” Chen said.

Hong Kong has entered what the German legal philosopher Carl Schmitt terms Ausnahmezustand, a state of exception or what we more commonly call a state of emergency. Chen is a fan of Schmitt, as are many anti-liberal intellectuals on the mainland. At this point, it must be said that like the great philosopher Martin Heidegger, Schmitt was a card-carrying member of the Nazi Party.

Hong Kong’s Ausnahmezustand justifies state intervention, which means the introduction of the national security law with its sweeping powers. Chen especially singles out the failure of the Hong Kong government to introduce its own security laws under Article 23 of the Basic Law. With Chief Executive Carrie Lam Cheng Yuet-ngor among his audience, though clothed in philosophical terms, he essentially blamed the Hong Kong government for failing to perform its most basic function that is its raison d’être.

Meanwhile, Tai had articulated the whole idea of laam chau long before the violent unrest of 2019. In an interview with The Wall Street Journal during the 2014 Occupy Central protests, he said Hong Kong people needed to convince the local business community to support their democratic demands. This meant threatening them with so much disruption that they could not conduct business at all. In the worst case, Hong Kong’s status as an international financial hub would be put at risk. The powerful local business lobby would have no choice but to ask the government to make democratic concessions.

If Occupy was laam chau as a threat, the street violence of 2019 was laam chau carried out in practice, because “this is very tragic but there is no alternative”, he wrote in his manifesto, “The ten steps to real ‘laam chau’ – the fate of Hong Kong”, last April. The manifesto is believed to have been cited by police in making his arrest.

A constitutional law specialist, Tai has long argued the rule of law and its democratic foundation could only be fully achieved and maintained in Hong Kong via political struggle outside the law. He initially advocated peaceful civil disobedience; that was in fact how he first conceptualised Occupy which ended up with protesters occupying multiple centres on Hong Kong Island and in Kowloon except the Central business district. Even today, the version of laam chau he advocates in his manifesto is non-violent in that it is more akin to a constitutional coup to paralyse the Hong Kong government and dislodge the chief executive under rules and procedures spelled out in the Basic Law.

Other versions of laam chau such as those advocated by the more radical elements of the anti-government protest movement involve street violence and physical confrontations such as those witnessed during the 2019 unrest.

Johannes Chan Man-mun, Tai’s former law colleague at HKU and fellow pro-democracy activist, has provided a concise series of constitutional arguments against the national security law, in “Does the Decision of the National People’s Congress on Enacting a National Security Law for Hong Kong Contravene the Basic Law?” published in the HKU Legal Scholarship Blog.

It’s well worth reading but I didn’t talk about it here because it is my contention that the fundamental insight – or if you like, extremism – of Chen and Tai, though they are the opposite of each other, is that Hong Kong’s social and political crises run so deep that they cannot be resolved by normal legal or constitutional means. So Chan’s discussion, though erudite, is really just academic.

That is the tragedy of Hong Kong.