Malaysia was formed on 16th September 1963 by combining Malaya, Singapore, Sabah & Sarawak (North Borneo States). The reason for its formation was to combat the communist expansion, creating a "bulwark" against any expansion from China or a possibly communist Indonesia in the future. Singapore withdrew from Malaysia in 1965 due to tensions, mostly between ethnic Chinese and Malayan ethnic groups. The state's formation was highly controversial, and both the Phillippines and Indonesia made claims to parts of the new state's territory. Internal rebellions supporting these claims or regional independence were brutally suppressed by Commonwealth forces, and three years of semi-war on the borders to Indonesia ensued. As a concession to the widespread opposition, Brunei was kept outside the Malaysian Federation, but remained under British military protection. The United States decisively agreed to support the formation of Malaysia after a 1964 secret diplomatic deal with the United Kingdom, in return for British support in Vietnam.
Malaysia has since maintained a delicate ethno-political balance, and developed a unique rule combining impressive economic growth and a political rule favouring ethnic Malayans and moderate Islam. In the late 1990s, considerable opposition to the existing system has been put down by the government, including democratic opposisition as well as proponents of a stricter Islamic rule.