Last month, in the days following the government’s legal challenge of Yau Wai-ching and Sixtus Baggio Leung Chung-hang’s Legislative Council oaths, some observers pointed out that Leung Chun-ying took his own oath of office incorrectly. Standing before then president Hu Jintao ( 胡錦濤 ) on July 1, 2012, Leung pledged to “be held accountable to the central people’s government of the People’s Republic of China and the special administrative region” without specifying, as the Oaths and Declarations Ordinance requires, that he was referring to the Hong Kong Special Administrative Region.

A writ has even been filed with the High Court, arguing that Leung Chun-ying’s oath was therefore invalid. That case will almost surely fail, but there is another case to be made about why the chief executive’s oath was invalid: not because he spoke the wrong words, but because he didn’t believe the words he spoke. As the Standing Committee of the National People’s Congress made clear in its interpretation of Article 104 of the Basic Law, “The oath taker must sincerely believe in and strictly abide by the relevant oath prescribed by law.”

Determining the sincerity of an oath-taker’s belief is the kind of subjective test that would normally bedevil common law judges trained to place themselves in the impartial shoes of the objectively reasonable man. But thanks to our High Court holding up – or being held down by – the Standing Committee’s interpretation, we now know how to measure sincerity. “The fundamental and essential question to be answered in determining the validity of the taking of an oath,” the court ruled, “is whether it can be seen objectively that the person taking the oath faithfully and truthfully commits and binds himself or herself to uphold and abide by the obligations set out in the oath.”

But, by the same token, an oath taker would also lack sincerity if he was not truthfully committed to the “two systems” part of “one country, two systems”. He would not be faithful to his oath if he did not bind himself to ensuring, as is also stated in the Basic Law preamble, that “the socialist system and policies will not be practised in Hong Kong”. And he would not be abiding by his obligations if he was not faithful to what the High Court itself stated was our “constitutional foundation”: that under Articles 16, 17, and 19 of the Basic Law, Hong Kong is vested with executive, legislative and judicial power, not some “transcendent” chief executive hovering above each branch of government.

Now that he will not have a second term by which to be judged, Leung Chun-ying, one could argue, has shown as much contempt for “two systems” as the two would-be lawmakers have shown for “one country”, only with fewer props and less salty language. Article 16 of the Basic Law requires Hong Kong to conduct administrative affairs “on its own”, yet just hours after the 2012 Lamma ferry disaster, Leung was inviting mainland authorities – which ultimately did nothing – to join the rescue effort.