Military exercises prepare militaries for the possibility of open conflict with enemies. More often, they are intended to deter conflict by warning adversaries that a country and its allies are prepared for battle and that aggression will be countered. A third message is sent to a different audience — allies, partners and the public. It is a reminder that a country takes its security responsibilities seriously and is ready to work alone or with allies to defend national interests.

All those messages are important and help us understand the recent flurry of military exercises in Northeast Asia. In March this year, North Korea sunk a South Korean Navy corvette, resulting in the loss of 47 lives. Last month, a North Korean artillery barrage on the island of Yeonpyeong claimed four lives, two of them civilians, and destroyed dozens of homes. It was the first North Korean strike on civilian territory in the South since the end of the Korean War. These were preceded by nuclear tests and missile tests.

South Korea and other concerned nations have responded with restraint. No overt military actions have been taken — despite growing demands by the South Korean public for Seoul to do so. Instead, the government of South Korean President Lee Myung Bak has pressed for a diplomatic solution to North Korean recklessness and belligerence. At the same time, Seoul has worked to signal Pyongyang that the provocations must stop.