The Volunteer Defense Corps (colloquially called
Or Sor in Thailand) was formally established on 10 February 1954 In 1974, the VDC was expanded by the
Internal Security Operations Command (ISOC) to urban areas to fight
communist insurgents. In the late-1980s, VDC strength was estimated at 33,000, down from a peak of about 52,000 in 1980. Part of the decrease in numbers was due to the formation of the
Thahan Phran, a paramilitary unit formed to counter communist insurgents, which absorbed some units of the VDC. Since 2004, the VDC has had a major role in fighting the
South Thailand insurgency. == Volunteer Defense Corps ranks ==