Southeast Asia ushered in a new era with the adoption of the ASEAN Charter in 2007 which entered into force a year later. At a time when ASEAN is transforming itself into a legal entity, unprecedented skirmishes broke out between two of its members on the border of Thailand and Cambodia. The background of this confrontation is an old dispute linked to the ancient Preah Vihear temple. The International Court of Justice ruled in 1962 that the ruins belong to Cambodia but made no decision concerning the adjacent land. To this day, Bangkok and Phnom Penh are making competing claims over this 4.6 km2 piece of land close to the border. The situation escalated when the Preah Vihear temple was designated a World Heritage Site in July 2008, following Cambodia's application to UNESCO. The upshot: several gun fights between October 2008 and June 2010 with at least eight soldiers killed. The contrast could not have been greater; officially proclaimed intstitutional change and the use of military force by two member states. The conflict says a lot about Cambodian and Thai foreign policy. But above all it allows conclusions to be drawn about the process of regional integration in Southeast Asia. There can be no doubt that the gap between rhetoric and reality is widening. From a medical viewpoint, the patient, in this case ASEAN, can be described as suffering from "institutional autism".