WASHINGTON >> The black hole of North Korea intelligence gathering is getting blacker.

When President Barack Obama and South Korea’s new president, Park Geun-hye, meet for the first time at the White House on Tuesday, intelligence officials and outside experts say, they will be working, by necessity, from a deeply incomplete understanding of their common adversary. At a time when the United States has learned to target drone strikes with increasing accuracy in Pakistan, and direct cyberweapons at specific nuclear centrifuges deep under the Iranian desert, its understanding of North Korea’s leadership and weapons systems has actually gotten worse.

The most recent intelligence failures included what administration officials now acknowledge was the CIA’s initial judgment that the North’s young new leader, Kim Jong Un, was probably more interested in economic reform than in following his father’s and grandfather’s "military first" policy of bolstering the North’s missile and nuclear arsenals, and threatening to use them unless the world came to its door.

At the same time, North Korea’s ability to hide critical facts about its weapons capability has improved. Nearly three months after the North’s third nuclear test dangerously escalated tensions on the Korean Peninsula, the U.S. remains unable to answer the most crucial question about the blast: whether the country figured out a way to enrich uranium and dramatically speed its nuclear buildup. The North has managed to contain the telltale gases that would have provided the answer, thwarting U.S. efforts to sniff out the evidence from Air Force sensors flown along the North Korean coast.

Since then, new mobile missile systems have appeared and then been whisked out of the view of spy satellites, leaving their whereabouts, to say nothing of their ability to reach Guam or the West Coast of the United States, uncertain. American officials said Monday that two missiles they once believed the North could launch imminently had been moved from launch sites, perhaps a sign that for now at least, the North wants to de-escalate.

In a sign of continuing confusion, the Defense Intelligence Agency — the Pentagon’s intelligence arm — recently declared with "moderate confidence" that the North can now shrink a nuclear warhead to fit onto one of those missiles, only to find its assessment disputed, in public, by both Obama and the director of national intelligence.

"We lack uniform agreement on assessing many things in North Korea," the director of national intelligence, James R. Clapper Jr., recently told Congress in a blunt assessment of the disagreements within the intelligence world. "Its actual nuclear capabilities are no exception."

The depth of the inability to figure out what is happening was reflected on Thursday in an unclassified Pentagon report to Congress on North Korea’s military capabilities, which read much like it had been written in the late 1980s. It also cast, by implication, significant doubt that returning to negotiations would do much good: "In North Korea’s view," it concluded, "the destruction of regimes such as Ceausescu, Hussein and Qaddafi was not an inevitable consequence of repressive government, but rather of a failure to secure the necessary capabilities to defend their respective autocratic regime’s survival."

But the more immediate concern is that Kim Jong Un could follow North Korea’s recent playbook and create another provocation — akin to the sinking of a South Korean navy ship in 2010 or the recent cyberattack on South Korean banks and news media companies. It took weeks of investigation before South Korea could blame the North for those past provocations.

More broadly, the lapses also raise a question of why, 63 years after the outbreak of the Korean War — itself a move the U.S. did not see coming — gathering information about the North has, in the words of one frequent intelligence consumer, "made Syria and Iran look like an open book."

At the same time, Kim has stepped up efforts to collect information about South Korea, as evidenced by the recent arrest in Seoul of a North Korean housewife who posed as a defector to the South.

"It’s an open question, who has penetrated whom more effectively," said Gary Samore, Obama’s former director for weapons of mass destruction.

North Korea has always been the hardest target, but the difficulties of figuring out what is happening now range from long-standing to brand new. The North has long been among the most brutal police states in the world, "very good at scouting human spies," says one U.S. intelligence official, "and finishing them off fast." Thus, South Korean intelligence services have a hard time inserting agents. It is all but impossible for an outsider to travel unnoticed to the North, a land of many checkpoints, few cars and a lot of neighborhood informers.

Moreover the technique that has been so useful in the case of Iran — recruiting scientists and others at international conferences — has been virtually impossible in the case of the North, whose officials rarely travel. When they do venture abroad, there are political officers and other minders who monitor what they do and say. Even the biggest potential bonanza — the arrival of cellphone networks — has been of limited use to intelligence gatherers.

And the technique used so effectively on Iran through 2010 — cyberespionage, and ultimately an attack on the centrifuges that run its nuclear enrichment center at Natanz — does not appear to have been as useful in North Korea. Computer use there is so limited — as is Internet access — that America’s technological advantage has yielded fewer results, according to officials familiar with the efforts. The North, meanwhile, has become more skilled at launching cyberattacks — some through China — at South Korean banks and television networks, including a devastating set of intrusions in March.

But the heart of the intelligence weakness centers on Kim, who is thought to be in his late 20s. The Chinese, who regularly invited his father, Kim Jong Il, to Beijing for consultations, praise and occasional dressing-downs, contend they have had few meetings with him. The only American to have dealt with him, quite famously, is Dennis Rodman, the former basketball star, whom the FBI was reported to have debriefed after he returned from a recent trip to North Korea.

"There was a time that he was trying to open up the nation with Western-style reforms," Japan’s defense minister, Itsunori Onodera, said of Kim Jong Un in an interview last week during a visit to Washington. "We were impressed that he admires Disneyland and loves American basketball. But then he realized he could not control the country, and he moved back to the military-first policy." Onodera said he was worried that "his father and his grandfather knew when to shift to ‘peace mode’ and shake hands; it seems that Kim Jong Un doesn’t know when to put his fist down."

In fact, in South Korea there is a theory that behind his baby-faced look and easy smile is a Machiavellian who already has top generals and party secretaries cowering at home, and is gambling that he can force Washington to accept the North as a nuclear power.

South Korean officials were surprised to conclude in recent months that despite Kim’s youth and inexperience, his government and party are exerting control over the military, which many regarded as too influential and too corrupt for that to occur. By some counts, two-thirds of the North’s senior generals have been demoted, replaced or shunted to less-powerful jobs; a few have been banished by the young leader. All have had to sign loyalty letters.

Yet the view that Kim has become as powerful as his father is not universal. "Who is in charge in North Korea? It’s hard to say," said a senior South Korean policymaker. "How strong is Kim Jong Un? We don’t know exactly. Who is giving orders in Pyongyang? Apparently, it’s Kim Jong Un, but we are not sure about the inner-circle decision-making process."

It is a measure of the varying interpretations inside the U.S. government that, testifying before the Senate Armed Services Committee, Adm. Samuel J. Locklear III, the head of the Pacific Command, called Kim " impetuous" and "more unpredictable" than his father. But speaking to the same committee, Lt. Gen. Michael T. Flynn, the Defense Intelligence Agency’s director, called Kim a leader "firmly in control" who "possesses a charisma that his father did not," and who understands realpolitik, including that he could not survive full-scale war.

Kim’s government has also played a complex game with U.S. intelligence agencies. He knew the West would be intensely interested in whether he tested another plutonium weapon or his first uranium weapon, the product of a new uranium-enrichment capacity that the North has only just unveiled.

But the test site was sealed to make it harder to gather atmospheric evidence. "It’s inevitable that sooner or later they will want us to know they can make a uranium weapon," said Samore, the former Obama adviser. "But no one knows quite why he is waiting." One possible explanation for the secrecy is that the technology is not working as advertised: A combination of rookie errors and sabotage have long slowed Iran’s efforts with the same technology.

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