The latest crisis emanating from Pyongyang is almost enough to make you nostalgic for Kim Jong-il who died at the end of 2011. Sure, he may have been a murderous tyrant who lived the high life while his people literally starved—but at least he was predictable and conservative in his actions. Not so his callow son and successor Kim Jong-un, who appears bent on escalating tensions with South Korea, the United States, and Japan so as to consolidate his shaky legitimacy to rule the North.

Young Kim’s regime has already said it will no longer abide by the Korean War armistice and that a “state of war” now exists on the peninsula. He has tested nuclear and ballistic weapons. He has cut off the redline telephones that maintained communications with the U.S. and South Korea. He has threatened to attack not only South Korea but the U.S.—in fact displaying supposed war plans toward that end in a doctored photo. He is also widely suspected of launching a cyber attack on South Korea.

Now he is even threatening to close the Kaesong complex where some 53,000 North Koreans are employed by South Korean companies—an important source of revenue for the cash-starved North. Kaesong has survived previous Korean crises and it is likely to survive this one, but it is a sign of how untested Kim Jong-un is that no one can be sure he won’t do something crazy and self-destructive. If Kaseong is closed, the odds of a North Korean attack on the South grow immeasurably—albeit, likely a limited attack, not an all-out offensive.

Faced with ample provocations, the Obama administration has adopted the right tone of firmness. The administration has certainly caught the world’s attention by sending B-2 and F-22 stealth aircraft to overfly South Korea—a clear signal of the kind of overwhelming military might that the U.S. and its allies can marshal if the North reignites active hostilities. The U.S. and South Korea must be wary of a spiral of reaction and counter-reaction that could spark a war that no one wants—but knuckling under now and giving Kim Jong-un further concessions, as the U.S. has done in the past, will only encourage more of this belligerent behavior in the future. Young Kim must learn that he is not going to be rewarded for his reckless militarism.