In December 1949, the government of the Republic of China moved to Taiwan where a force of 300,000 Nationalist troops was already stationed.
Prior to Chiang’s arrival, the Taiwan Garrison Command proclaimed an Emergency Decree (martial law) throughout the province.
The relocated KMT government was marginalized by the United States until after the outbreak of war in Korea in June 1950.
Secretary of State Acheson made clear the US position in a January 1950 speech when he stated that the Philippines and Japan, lying within what he called the American “defense perimeter,” were
inescapable responsibilities, part of a defense perimeter which starts from the Philippines and continues through the Ryuku Archipelago, which includes its main bastion, Okinawa. Then it bends back through Japan and the Aleutian Island chain to Alaska.
He went on to say that
so far as the military security of other areas in the Pacific is concerned, it must be clear that no person can guarantee these areas against military attack.
Thus, both Taiwan and Korea were excluded from the area that would be defended by the United States.
So far as the demography of the 1949 migration is concerned, it is estimated that about one million military personnel retreated from the mainland along with about one million non-military individuals.
This population movement immediately changed the face of Taipei since, while there was a major effort to channel migrants into rural areas, most exiles settled in cities, many of them in the capital.
The migrants began to dominate the politics and society of Taipei almost immediately for, even though they had little knowledge of or ties to Taiwan, they brought with them skills which enabled them to fill the vacuum left by the repatriated Japanese.
The islanders had no political movement or armed force to challenge their rule. Facing no internal opposition and having no social base within Taiwan, the Nationalist-mainlander government had unusually wide room for maneuvering. And it had an unusually dominant position in the economy, for it inherited all the productive assets and control mechanisms that the Japanese had built up over fifty years. The monopolies owned by the colonial administration, Japanese-owned shares in industrial enterprises, Japanese-owned lands — all passed to the incoming government.
The mainland regime gained power quickly.
Taiwan became a one-party state under the military leadership of Chiang Kai-shek. This action was contrary to the general expectation that, at the end of World War II, the entire island of Taiwan, long subject to Japanese military control, would return to civilian rule.
The establishment of martial law and the influx of one million military personnel from the mainland meant that this would not come to pass. Rather the island as a whole was to remain under martial law for almost fifty years.
It is worth noting that, while the Americans and the Soviets were certainly involved in the Chinese civil war, they did not play and explicit role in the militarization of Taipei between 1945 and 1950. Soon, though, militarism was to become linked to Cold War realities, and the island’s major transformation would begin.