Look when even China has formally said "you are doing stupid things and we dont support you" you probably need to re-evaluate just how far your head is lodged beyond your colon.
I dont think our president, Obama or anyone else, would be well served for stepping into a formal talk with the NK leadership. The issues they are mainly pissed about are regional, all we would do is add to their frustration since they see us as the ones cutting off their pipeline of supplies, money, etc. I agree perhaps a global leadership, G20 countries maybe, should sit down with them and say something like "look, you cannot win this, even your allies are at this table across from you. This is check and mate, you need to back it down and listen"
End of the day, the people of NK are the ones that suffer and not much we can do would end that without considerably increasing it first.