This article studies how the Hong Kong Court of Final Appeal has come to develop a sophisticated judicial gloss on the provisions of the Basic Law, Hong Kong’s constitutional document, in ways unforeseen by the Chinese National People’s Congress that enacted it. The ascendancy of constitutional common law in Hong Kong after the end of British rule is remarkable when considered in light of the continuing denial of democratic self-rule by China’s authoritarian Party-state. This article argues that the profusion of political transaction costs due to the fragmentation of the ruling elite and state-society discord consequent to the resumption of Chinese sovereignty has created the requisite space for the Court to craft, with impunity, consequential yet politically realistic doctrines bearing on such weighty matters as constitutional interpretation, central-local relations, separation of powers, and rights protection