A republic established on the southern half of the Korean peninsula in 1948 when United Nations-sponsored elections were held in the part of the country where U.S. troops had accepted the surrender of the Japanese occupying forces from World War II a few years earlier. (The northern part, where Soviet forces ahd accepted the surrender, had refused to let U.N. inspectors in for the elections.) There were a few years of outright fighting in which other countries got involved (the Korean War which ended inconclusively.) Even 50 years later, there's still a lot of tension between North and South.
While South Korea did not become a Communist country like North Korea, it has hardly been an ideal democracy either. As eliserh puts it, "It's worth pointing out that South Korea actually became a republic in much the same way that North Korea is a 'republic', i.e. in name only. South Korea remained under fascist rule until the early eighties, and still has many remnants of fascism in its legal system, such as the National Security Act, which allows pretty much anyone to be taken into custody at any time for any reason without trial or charge, and allows political dissidents to be put to death." | 
