The RP-US Visiting Forces Agreement, or VFA, is a 1999 agreement between the Philippines and the United States building on the 1951 US-Philippines Mutual Defense Treaty (MDT). One article of the MDT specifies that the two countries will maintain and develop their individual and collective capacity to resist armed attack. Therefore, US and Philippine personnel visit the territory of the other to train jointly. The VFA addresses the treatment of personnel from one signatory who are accused of having committed crimes while visiting the territory of the other. Partly as a result of the Volunteers Against Crimes and Corruptions controversy growing out of this case, especially on the custody issue, the Congress of the Philippines has considered terminating the VFA.