The eight-year term limit was meant to target former Prime Minister Thaksin Shinawatra, a populist billionaire who was ousted by a 2006 military coup but whose political machine remains powerful. The army in 2014 also ousted the government of Thaksin’s sister, Yingluck Shinawatra, who was forced from office shortly before the takeover by a controversial court decision.
Thailand’s traditional conservative ruling class, including the military, felt that Thaksin’s popularity posed a threat to the country’s monarchy as well as their own influence. The courts have been stalwart defenders of the established order and ruled consistently against Thaksin and other challengers.
Source: