[1][2] On 6 October 1973, Thirayuth and 12 other student activists were arrested by the Praphas government for sedition after they distributed leaflets demanding a new constitution.
The demonstrations reached their peak on 13 October, when about 400,000 protesters gathered in front of the Democracy Monument and the parliament building.
Thirayuth increasingly became critical of the king, noting in a broadcast on 1 April 1977 that the monarchy was "obsolete and deteriorating", and that "I think that if our people were to destroy it, there would be no adverse effects".
After the CPT dissolved itself in the early-1980s, Thirayuth returned to the mainstream of Thai intellectual life, renouncing socialism and rejecting his anti-monarchical statements.
Thirayuth was an outspoken critic of prime minister Thaksin Shinawatra (2001–2006), for whose rule he coined the term "Thaksinocracy".