"The purpose and scope of this CRS [Congressional Research Service] report is to provide a succinct overview with analysis of the issues in the U.S.-Taiwan relationship. This report will be updated as warranted. Taiwan formally calls itself the sovereign Republic of China (ROC), tracing its political lineage to the ROC set up after the revolution in 1911 in China. The ROC government retreated to Taipei in 1949. The United States recognized the ROC until the end of 1978 and has maintained a non-diplomatic relationship with Taiwan after recognition of the People's Republic of China (PRC) in Beijing in 1979. The State Department claims an 'unofficial' U.S. relationship with Taiwan, despite official contacts that include arms sales. The Taiwan Relations Act (TRA) of 1979, P.L. [Public Law] 96-8, has governed policy in the absence of a diplomatic relationship or a defense treaty. Other key statements that guide policy are the three U.S.-PRC Joint Communiqués of 1972, 1979, and 1982; as well as the 'Six Assurances' of 1982."
CRS Report for Congress, R41952
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html