After World War II, Korea was divided into two states. The Soviet backed North and the US backed south. In 1950, the Korean war broke out because The North and Kim Il Sung wanted to reunite Korea but under communist rule.
The US got involved In the conflict to stop the expansion of communism and since the conflict came to a ceasefire in 1953 tensions have been high between North Korea and the US with the North always threatening with war with there being a number of skirmishes between the South and the North. In 1968, USS Pueblo, a US Intelligence ship, was captured by the North.
Since the start of this century we have seen a huge advancement in nuclear and missile technology within North Korea with the first nuclear weapon test happening in 2006. Currently, the nuclear tests that have been performed by North Korea, although they can cause some destruction, are far less powerful than the nuclear bombs that hit Nagasaki and Hiroshima.
But is North Korea a threat to international security?
To answer this question we need to understand why North Korea is pursuing nuclear weapons. This is a matter of security dilemma between North Korea and the US. The security dilemma is one of the most important concepts in international relations theory.
Security dilemma involves a "two-level strategic predicament," a "dilemma of interpretation" and a "dilemma of response." A Dilemma of interpretation arises when the military preparations of one state creates an unresolvable uncertainty in the mind of another as to whether those preparations are for "defensive" purposes only (to maintain security) or whether they are for "offensive" purposes (to change the status quo). A dilemma of response arises when policy makers have to decide whether to respond to a dilemma of interpretation by either signalling that they will respond in kind or signalling reassurance.
We see this between North Korea and the US. Currently, we see military preparations in North Korea with the expansion of its nuclear capabilities but for the US this raises the question whether this is for defensive purposes or for aggressive purposes?
I believe that this growth in nuclear armament is for defensive purposes. For states like the US, UK , India, Pakistan etc, it is to guarantee its national security and I believe this is what is happening in North Korea because they feeling threatened by the US. With the United States' massive military budget and the superiority of its military, North Korea would not stand a chance through conventional warfare.
I don't believe that North Korea has an offensive purpose because I don't believe they have the capabilities for it. Their military is very outdated and they do not have the economy for an offensive operation and if somehow they did mange to reunite Korean it would be very hard to keep control of the state under communist rule, even now I believe that people inside North Korea are slowly starting to learn the truth with the advancement of technology it is becoming easier for information to enter the state and it will become harder for Kim to keep control.
I believe that Kim Jung-Un knows the risk of using nuclear weapons and would not actually use them even though he says he is prepared to use them. Just like all other states that have nuclear weapons, they will all say that they will use them even though they probably won't. Because if they say they won't use them, then they will become invalid and won't be a deterrence and would be a waste of money. But we can not rule it out that it could be for an offensive purpose but this is highly unlikely.