There has been a lot of speculation on the instigating factors for the current Korea situation. As with everything to do with North Korea, there are multiple theories - some sources indicate that the artillery attack on Yeonpyeong was instigated by a live-fire exercise the South was executing in disputed waters (within earshot of the Northern mainland). Others propose that this attack was used as an opportunity for Kim's heir apparent, Kim Jung-un, who holds the rank of a 4-star general but has very little military experience, to show his mettle. Both these theories are predicated upon the siege mentality attested to in North Korean culture by defectors, and to the idea of using foreign policy to alter domestic opinion.
This brings to mind other exercises in foreign policy that have been driven primarily by domestic concerns. For instance, the regular "Death to America" coke-pouring protests that Iran used to spur nationalist feeling before important events, or the renaming of French Fries to "Freedom Fries" by the US Senate.
