It did not take long for North Korea to test South Korea's new president, Mr. Lee Myung Bak. After Mr. Lee warned the Pyongyang government that he would condition economic cooperation on dismantlement of its nuclear-weapons program, North Korea expelled South Korean officials working at a joint industrial complex. Shortly after, it test fired several short-range missiles. Then on Sunday it threatened the South with destruction after Seoul's top military officer said his country would strike a suspected North Korean nuclear-weapons site if the North attempted to carry out a nuclear attack.

More such challenges can be expected if Mr. Lee sticks to his harder line against the North and demands greater reciprocity in inter-Korean relations. It is not clear if Mr. Lee and the South Korean public have the stomach for a return to a more confrontational approach to the North: Pyongyang will do its best to raise the stakes.

During his campaign, Mr. Lee, a conservative, promised a re-evaluation of the North Korea policies of his predecessors, Presidents Kim Dae Jung and Roh Moo Hyun. Those men believed that Seoul should reach out to Pyongyang to diminish its insecurity. If it felt less threatened, the theory went, North Korea would adopt reforms and become a better international citizen. Ten years of "sunshine" — named after Aesop's tale — disappointed many South Koreans. While there is no desire to resurrect the animosity that marked inter-Korean relations prior to 1992, many in the South believe that the relationship has been unequal, with Seoul offering olive branches, aid and assistance that the North has pocketed while offering little in return. South Koreans want recognition of their help and reciprocity from the North.