THE CYCLE of actions with which North Korea has manipulated the United States for nearly two decades remains unchanged: It promises a freeze on its nuclear and missile programs in exchange for economic and diplomatic concessions; it breaks those promises; and then it lashes out when it is held accountable.

Now the cycle has been radically compressed. Only 16 days elapsed from the announcement of a freeze-for-food deal between the Obama administration and Pyongyang to the North’s revelation that it would launch a ballistic missile. The launch is expected as early as Thursday, and there are signs that it could be followed by a nuclear weapons test.

The fact that North Korea is rupturing the latest bargain before it has obtained any of the food it was promised suggests to some experts that the new regime of Kim Jong Eun may be unsteady or afflicted by infighting. Another possible explanation is that the Obama administration allowed itself to be set up by the regime’s negotiators. North Korea maintains (as it has on previous occasions) that the missile launch has a civilian purpose, the positioning of a satellite, and therefore does not break the Feb. 29 agreement. The Obama administration lacks a joint statement or text clearly refuting this, having failed to insist on one when it made the deal.

The regime may calculate that this ambiguity, combined with its prompt compliance with its pledge to invite international nuclear inspectors, may weaken any response to the missile launch by the U.N. Security Council. If the council or the United States reacts with condemnation, a suspension of the food aid or fresh sanctions, the North will have its cue to declare itself betrayed and conduct a nuclear test.

Having made the mistake of breaking with its previous policy of refusing to “buy the same horse” from North Korea, the administration can now probably do little to stop either provocation. Some suggest the missile should be shot down; but that would risk a failure of the U.S. anti-missile system and a military response by the North that the United States and its allies are not prepared for. It’s also not likely that the United States can inflict major punishment on the North through new sanctions or persuade China to do so.

The administration should, however, try again to convince Beijing that its bet on the 28-year-old Mr. Kim is a recipe for the instability it says it wants to avoid. The Treasury Department should look for ways to squeeze the finances of the regime and its leaders, as the George W. Bush administration managed to do before it succumbed to the North’s bait-and-switch diplomacy. Perhaps after this episode, too, the United States can finally face the fact that seeking to negotiate deals with North Korea is invariably counterproductive. The administration explained this latest bargain by saying it wished to test the intentions of the new leader. When the missile is launched, it will have a clear understanding.