North Korea's only play on the world stage is the threat that possibly they are unstable enough to use a nuclear weapon. This threat allows them to command a certain amount of attention and simply stated is the only card they have to play. If they were to use a nuclear device of some sort they would lose that card and the repercussions against them would be more than the ruling factions are willing to pay. The Kim family and their supporters will not jeopardize their position by doing anything that would automatically ensure their downfall.
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