Why are South Koreans losing faith in America’s nuclear umbrella?

Seoul CNN — They have them, so we need them. That is the fundamental argument for South Koreans who want their country to develop its own nuclear weapons. It's about the need to protect themselves from an aggressive northern neighbor that is already a nuclear power in all but name and whose leader Kim Jong Un has vowed an "exponential increase" in his arsenal. The counter-argument, which has has long stopped Seoul from pursuing the bomb, lies in the likely consequences. Developing nukes would not only upset the country's relationship with the United States, it would likely invite sanctions that…