North Korea and South Korea exchanged artillery fire near their disputed border in the Yellow Sea/West Sea on Nov. 23. The incident raises several questions, not the least of which is whether Pyongyang is attempting to move the real "red line" for conventional weapons engagements, just as it has managed to move the limit of "acceptable" behavior regarding its nuclear program.

The incident damaged as many as 100 homes and thus far has killed two South Korean soldiers and two civilians with several others, including some civilians, wounded. The South Korean government convened an emergency cabinet meeting soon after the incident and called for the prevention of escalation. It later warned of "stern retaliation" if North Korea launches additional attacks.

Pyongyang responded by threatening to launch additional strikes, and accused South Korea and the United States of planning to invade North Korea, in reference to the joint Hoguk military exercises currently under way in different locations across South Korea.

The incident is the latest in a series of provocations by Pyongyang near the NLL this year following the sinking of the South Korean warship Cheonan in March. Over the past several years, the NLL has been a major hotspot. While most border incidents have been low-level skirmishes, such as the November 2009 naval episode, a steady escalation of hostilities culminated in the sinking of the Cheonan. The Nov. 23 attack on the South Korean island of Yeonpyeongdo represents another escalation; similar shellings in the past were for show and often merely involved shooting into the sea, but this attack targeted a military base. It also comes amid an atmosphere of higher tensions surrounding the revelation of active North Korean uranium enrichment facilities, South Korea’s disavowal of its Sunshine Policy of warming ties with the North and an ongoing power succession in Pyongyang.

Over the years, North Korea has slowly moved the "red line" regarding its missile program and nuclear development. It was always said that North Korea would never test a nuclear weapon because it would cross a line that the United States had set. Yet North Korea did test a nuclear weapon in October 2006, and then another in May 2009, without facing any dire consequences. This indicates that the red line for the nuclear program was either moved, or was rhetorical. The main question after the Nov. 23 attack is whether Pyongyang is attempting to move the red line for conventional attacks. If North Korea is attempting to raise the threshold for a response to such action, it could be playing a very dangerous game.

However, the threat North Korea’s nuclear program poses is more theoretical than the threat posed by conventional weapons engagements. Just as it seems that a North Korean nuclear test would not result in military action, the Cheonan sinking and the Nov. 23 attack seem to show that an "unprovoked" North Korean attack also will not lead to military retaliation. If this pattern holds, it means North Korea could decide to move from sea-based to land-based clashes, shell border positions across the Demilitarized Zone or take any number of other actions that certainly are not theoretical.

The questions STRATFOR is focusing on after the Nov. 23 attack are as follows:

• Is North Korea attempting to test or push back against limits on conventional attacks? If so, are these attacks meant to test South Korea and its allies ahead of an all-out military action, or is the North seeking a political response as it has with its nuclear program? If the former, we must reassess North Korea’s behavior and ascertain whether the North Koreans are preparing to try a military action against South Korea — perhaps trying to seize one or more of the five South Korean islands along the NLL. If the latter, then at what point will they actually cross a red line that will trigger a response?

• Is South Korea content to constantly redefine "acceptable" North Korean actions? Does South Korea see something in the North that we do not? The South Koreans have good awareness of what is going on in North Korea, and vice versa. The two sides are having a conversation about something and using limited conventional force to get a point across. We should focus on what the underlying issue is.

• What is it that South Korea is afraid of in the North? North Korea gives an American a guided tour of a uranium enrichment facility, then fires across the NLL a couple of days after the news breaks. The South does not respond. It seems that South Korea is afraid of either real power or real weakness in the North, but we do not know which.

This is reprinted with permission from Stratfor Global Intelligence (www.stratfor.com)