This paper examines the Thai state's approach in tackling the separatist movements in Thailand's predominantly Malay-Muslim South. Developing upon Lewis et al.'s concept of Authoritarian Conflict Management, I argue that the state has largely employed an authoritarian mode to respond to the resurgence of violent rebellion since 2004, with the military taking dominant roles. Illiberal peace-building, largely influenced by Thai Cold War counterinsurgency doctrine, has extended not only to spatial, discursive and economic domains, but also to the legal realm. A nationally driven peace process initiated in 2013 was a departure from the state's long-standing modus operandi. It was a period in which national elites experimented with a relatively more liberal approach. The Kuala Lumpur-facilitated process sparked both inter- and intra-group contention and soon collapsed due to the effect of unending battle between the so-called democracy camp and the royalist-establishment camp. The trajectory of the formalised dialogue took a significant turn after the 2014 coup. While retaining the process, the military regime turned it into an extended domain of illiberal peace-building.