Thailand has seen considerable progress in the rule of law since the seminal 1997 constitution. Yet persistent political instability suggests that as yet the country does not think of the rule of law as binding. What is likely to happen in Thailand with the rule of law, and with governance generally? The argument advanced here is that rule of law principles must contend with the realisation that the traditional Thai trinity-nation, religion and king-has become an inviolable state ideology. Political actors, often aligned with the monarchy, have been using each element of the trinity to undermine both rule of law principles and democratic institutions. Now that long-serving monarch King Bhumibol (Rama IX) has been succeeded by his son King Varijalongkorn, it seems an appropriate time to examine current battles about the meaning of the rule of law and broader struggles for control between elites and popular groups based on competing visions for the state-a problem not only in Thailand but in the region as a whole.