I cannot imagine doing the North doing that as it would not gain them anything by attacking thier neighbours they would only end up in a much more messy situation also an attack on countries like Japan would out strains on the North's relations with it's only ally namely China. As far as hitting the USA the North has had that ability for nearly 6 years it is known that they could easily hit the East coast of the US very easily, I think that this is partly why Bush was so desperate for the son of star wars to be developed.
The truth is that the N.Korean governmnet could actually flourish whil still keeping it's basic communist links, you only have to look at China still communist but with an open economy.
Did they prove to the world that they have a missile capable of reaching the US or that's just their talks? Keep in mind they may and probably do bluff a lot.
That messy situation you are talking would be hell. Because neighboring countries, together with the US, would destroy the regime as soon as it tries attacking any other state in the region or the World. And N.Korean leadership perfectfly understands that. All they can do is talk and ask for money.
MI6 and the CIA have confirmed that they do have missles capable of reaching Western Europe and the East Coast of the USA.
As for the messy situation you have given the perfect reason why N.Korea would not attack Asian neighbours, because they could not handle that kind of firepower, the N.Korean leaders are not stupid and know that, they have no problem with the rest of Asia ( in fact they have good relations with at least 3 other countries and have never threatend any other country in that area apart from the south) so therefore no reason to attack them, they only have a problem with the USA.
Yeah that is most definitly part of the problem. When I said that the North had a problem with the US I was going on the official line from N. Korea which was that the nukes were there to prevent an attack from the US.