This principle is addressed in the current Thai Constitution B.E. 2550 under Article 190.
Article 190 paragraph 2 – “Any treaty, which provides for a change in the Thai territories or extraterritorial areas in which the Kingdom has the sovereign rights or any jurisdiction through treaty or international law, or the Kingdom is required to enact an Act for implementation of the treaty or has vast impact on the county’s economic and social stability, or has a significant binding effect upon the trade, investment or budget of the country, it shall be approved by the National Assembly…”