Today's Minneapolis Star-Tribune letter of the day starts out with
Time and time again, the United Nations proves false the notion that nations working together can prevent atrocities against humanity.
and goes on to chide the UN for not taking a direct hand in helping the people of Myanmar. In doing that, the writer shows a basic lack of understanding of just how powerless diplomacy is.
Fundamentally, diplomacy cannot change a nation's behavior unless it's backed up by a credible threat of force. Merely asking the junta of Myanmar to please stop hoarding supplies and allow those with experience to distribute them to the people who need them the most is not going to work. They have no incentive to: the world hates them already, so why should they change? Expecting diplomacy to change the course that North Korea is taking is similarly foolish - they're showing themselves to be untrustworthy.
If a government is convinced it's acting in its own best interests, you won't talk them out of a course of action. The best you can do is threaten them with something they'll have to take notice of - and then carry out the threat when they call you on it. Anything less is wishful thinking.