It was inevitable, really: Pyongyang missed the yearend deadline to declare its nuclear programs and facilities and disable nuclear facilities at Yongbyon. Instead, it railed against the United States, demanding that it end its "hostile policies" toward North Korea. North Korea's prevarications are not reason enough — yet — to give up on the six-party talks. But all the other participants in those talks should make it clear that Pyongyang is expected to honor its obligations — and only then will they match "action for action."
Pyongyang missed two deadlines. The first concerns the disablement of its nuclear facilities. That process is under way — the Yongbyon reactor was shut down last summer — but it is taking longer than anticipated as a result of technical concerns about cooling fuel rods. The second requires a complete declaration of all nuclear activities, a crucial step since Pyongyang must declare all of its programs so that the rest of the world can have confidence that the Korean Peninsula has been denuclearized.
U.S. intelligence suspects North Korea of purchasing materials that can be used for uranium enrichment and cooperating with Syria. A failure to clarify both of these concerns could jeopardize the deal.