To be fair, it is important to remember that the "police action" with North Korea, (not a war) ended with an armistice and not a peace agreement. However, there was a war between North and South Korea. North Korea considers this an ongoing war with the United States as its enemy. This has been true since the ending of hostilities in the 1950's. Since that time North Korea has been a rogue nation believing that the US would eventually re-start the conflict and reunify the country with South Korea.
Many US administrations have tried to negotiate with NK but they have done so with carrots and not sticks. We give them money, food, and try two party, six party diplomacy and they continue to starve their people and disregard any agreements. Meanwhile the North Korean leaders have been at work spending our resources on missiles and nuclear weapons. So, the mantra that North Korea should not be allowed to be a nuclear nation has been a dismal failure. That horse left the barn a long time ago!
So, what can we do to ease the threat to the US and its allies? The answer is clearly complicated and will take a measured approach. One possibility is to use the UN which is a paper tiger and bowl of moving jelly to go beyond sanctions and send diplomats to broker a controlled nuclear state. (Both the North and South were admitted to the general assembly in 1991). During the initial conflict the UN did send peacekeepers from multiple countries to South Korea. But, now consider the second option and that is China. They control the destiny of the North and are the main pipeline of food and energy. But wait! Didn't the Chinese send troops and arms to North Korea during the conflict? Yes they did, and they want to keep a foothold in that part of the Pacific. But so did Russia, another unlikely partner with the US! So, we are working with limited options, but should we not do? Act irrationally!
And now we get to the kids in a sandbox. Both Kim Jon-un and the president are acting like kids in elementary school. Who has the biggest stick and who will poke the status quo in North Korea? Kim Jon-un has no rules in his leadership role but our president does have to follow accepted protocols. But he continues to draw lines in the sand and they are constantly crossed without consequence. NK keeps sending ICBM's over Japan's airspace and the UN slaps his hand again. The president calls him Rocket Man and threatens to eliminate North Korea. This is not diplomacy, it is idiocy! BTW, North Korea's UN ambassador has said that the president has declared war on NK. In point of fact only Congress can declare war!
The world is watching what was a respected democracy being weakened by a twitter account. Please take away the presidents tweets and educate him about how to be an effective leader and not a school child.