In its contingency planning, Washington for the first time is treating North Korea as a nuclear-armed opponent, the New York Times reported on Thursday.
Specifics about the most recent revision of the "OpPlan 5029" strategy for a potential new Korean War are classified. Some unidentified officials talked to the newspaper about aspects of the "what-if" scenarios, which imagine a possibility for Pyongyang to build a simple atomic weapon and attempt to deliver it by ship or truck.
The development comes as Washington and its allies in East Asia steadfastly refuse to characterize North Korea as a nuclear-armed state.
U.S. intelligence officials do not think Pyongyang has developed the ability to miniaturize nuclear arms enough to fit on a ballistic missile. The North, however, could make headway in that respect if it test-detonates a fourth atomic device -- as appears increasingly likely.
Behind closed doors, Obama administration officials are acknowledging the longtime policy of "strategic patience" toward North Korea has been unsuccessful, the Times reported.
"We have failed," Evans Revere, a former senior official for East Asian issues in the George W. Bush administration, said in an interview. "For two decades our policy has been to keep the North Koreans from developing nuclear weapons. It's now clear there is no way they will give them up. ... So now what?"
A recent attempt by the National Security Council to develop a new plan for ending the North Korea nuclear impasse came up empty when it was determined that all other potential policy deviations were worse than the current posture, according to the Times.
"We're stuck," said one individual who took part in the review.
A move by ruler Kim Jong Un to focus more on mobile missiles instead of stationary ones has meant the United States has a harder time detecting when a missile firing is imminent. The launchers are routinely moved between tunnels, making them harder to monitor by satellite, defense officials said.
"He's gone to school on how we operate," said Army Gen. Curtis Scaparrotti, who commands U.S. forces on the Korean Peninsula.