The North Korean state had two stepparents: the Soviet Union, which brought Kim Il-sung to power in 1945, and China, which prevented his overthrow by UN forces in 1950. While China refused to help North Korea acquire nukes, the Soviets were willing to help Pyongyang build a civilian nuclear reactor at Yongbyon, which was completed in 1965.

However, it’s not a simple matter to adapt civilian nuclear technology to military purposes: it’s easier to refine less concentrated nuclear fuel, adapted for release over time, than highly refined weapons-grade materials, which are primed to release energy all at once. North Korea nonetheless went about discreetly shopping for technology in Europe, Asia and the Middle East, and by the 1980s had made strides refining weapons-grade plutonium at Yongbyon—producing a small quantity by the early 1990s.

Nuclear weapons also require a reliable delivery system; again China and the Soviet Union declined to furnish ballistic missiles, but Pyongyang was able to acquire secondhand Scud missiles from Egypt in the late 1970s, and successfully reverse-engineered them by the mid-1980s, kicking off its now-infamous ballistic-missile program.

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Back in 1985, North Korea had declared it would accede to the Nuclear Non-Proliferation Treaty, improving its access to civilian nuclear technology, with full compliance scheduled for 1992. However, when International Atomic Energy Association inspectors arrived, they soon found discrepancies with North Korea’s reported nuclear materials. Their attempts to visit North Korean nuclear sites were repeatedly barred. IAEA head Hans Blix proclaimed North Korea to be not in compliance with the NPT.

Caught red-handed in a lie, Pyongyang responded with a characteristic defiance: in March 1993 it declared it was withdrawing from the NPT, and kicked out the weapons inspectors.

North Korea’s Post–Cold War Blues

But North Korea was in a uniquely vulnerable position in 1993. The collapse of the Soviet Union had brought an end to the generous economic assistance that had kept its economy functioning. This, combined with floods, bad harvests and limited arable land, led to a devastating famine, which over the course of the next five years likely resulted in the death of half a million, though some estimates run much higher. Desperate North Koreans resorted to eating frogs (not a traditional dish), which rapidly disappeared as a result; many survivor accounts describe elderly relatives starving themselves to death so that young family members would receive enough food to survive.

At the same time, North Korea experienced its first transition of power in its nearly half-century-long history when Kim Il-sung died on July 8, 1994. Though Kim Jong-il’s succession may appear a foregone conclusion today, it took four years for him to fully consolidate his control. These unstable conditions meant Pyongyang was especially desperate to end its economic isolation.

In October 1994, State Department negotiators led by Ambassador-at-Large Robert Gallucci negotiated what was termed the Agreed Framework. The concise two-page document laid out a four-point program:

(1) North Korea would cancel construction of two five-hundred-megawatt graphite-moderated reactors that were clearly designed for military purposes, despite ingenuous claims to the contrary. In compensation, the United States, South Korea and Japan would form the Korean Peninsula Energy Development Organization (KEDO), a consortium that would build two one-thousand-megawatt civilian light-water reactors in North Korea—and the United States would furnish Pyongyang with five hundred thousand tons of heavy fuel oil annually.

(2) The United States and North Korea would move toward normalizing relations and lifting economic sanctions.

(3) North Korea and the United States would exchange assurances not to employ nuclear weapons, and North-South dialogue would occur to de-escalate tensions.

(4) North Korea would accede to the NPT treaty, set aside its weapons-grade plutonium for eventual disposal and allow inspectors access to its nuclear facilities.

This was seen as an acceptable compromise, because light-water reactor technology was less easily converted to military purposes. After some delays, Pyongyang did follow through by canceling the two new reactors, granting access to IAEA inspectors and setting aside its extant nuclear fuel stocks. U.S. intelligence reports estimated that the agreement prevented North Korea from building up to a hundred nuclear weapons in the next decade.

Problem solved! But both Washington and North Korea failed to follow through, in both the letter and spirit of the agreement.

Clinton, Congress and Framework Follow-up

The Agreed Framework was not technically a “treaty,” and thus did not require a vote in Congress. This was approached was devised by the Clinton administration to avoid having the deal scrubbed by partisan politics. Indeed, two weeks after the agreement was signed, a new round of legislative elections swept the Republican Party to control of the U.S. House and Senate. Republican senators and representatives were fiercely critical of the deal, arguing it rewarded North Korean misbehavior.

The problem remained that following through on many of the U.S. promises in the deal did, in fact, require congressional approval. Though funding was grudgingly forthcoming for the fue-oil shipments, these often arrived after promised deadlines. Seoul ended up footing most of the $4.6 billion bill for the light-water reactors, but progress by KEDO proved slow, and only preliminary work had begun by the provisional “due date” of 2003.

Perceiving further concessions as being politically untenable, the Clinton administration largely gave up on following through with the rest of the Agreed Framework, and made few serious attempts at lifting sanctions or formally ending the Korean War—which was still officially ongoing a half century after fighting had ended. Later, some Clinton-era officials admitted they had expected North Korea to collapse on its own before the light-water reactors were ever constructed.

But what Washington regarded as vaguely worded rhetoric about warmer relations was seen as a vital assurance to an insecure, famine-wracked North Korea. Pyongyang interpreted the failure of what was then the world’s only superpower to follow through in the most paranoid light.

North Korean Uranium Cheating

Washington may not have sustained serious engagement with North Korea, but Seoul bent over backwards, making friendly gestures and providing economic aid through the “Sunshine Policy” under the liberal governments of Kim Dae-jung and Roh Moo-hyun from 1998 to 2008. International food aid would help bring the North Korean famine under control by 1998.

Though Pyongyang accepted the aid, it strangely did not cease its provocative and often-violent military activities. North Korean troops shot down a straying American helicopter in 1994—and demanded that Washington apologize. In 1996, a North Korean submarine ran aground in Gangneung, South Korea, while deploying commandos who proceeded to kill fourteen South Koreans and attempted to flee on foot back across the Demilitarized Zone. Two more submarine infiltrations ended bloodily in 1998, followed by naval battles near Yeonpyeong in 1999 and 2002.

At the same time, having had its plutonium-bomb program constrained by the agreement, North Korea instead secretly began work on producing a uranium bomb.

The “Little Boy” bomb dropped on Hiroshima was a uranium weapon, but today nearly all nuclear weapons use plutonium-239. Though the uranium bomb amounted to a slower, less effective path to nuclear weaponry, it still could be developed into deadly weapons. Pakistani nuclear physicist Abdul Qadeer Khan transferred nuclear technology to North Korea through a proliferation network between 1991 and 1997, both before and after the Framework—a move that he claims was ordered by the Pakistani government in exchange for North Korea’s ballistic-missile technology.

Kim Jong-il and Bush Blow Up the Framework

In the final year of the Clinton administration, it belatedly followed through with making assurances of “no hostile intent” from U.S. military forces and removing certain sanctions. However, the former measure was rescinded the following year under the George W. Bush administration, which reinstated North Korea as a potential target in its Nuclear Posture Review.

Though Secretary of State Colin Powell was in favor of continuing engagement with Pyongyang, he was overruled by neoconservatives in the Bush administration, who favored confrontation and possible “regime change” (i.e., war). After the 9/11 attacks, North Korea was labeled part of the “Axis of Evil.”

The CIA had pieced together evidence of the North Korean uranium-enrichment program, including shipments of centrifuges from Pakistan and Russia. In December 2002, James Kelly, the assistant secretary of state for East Asia, went to Pyongyang and confronted a negotiator with evidence of North Korea’s uranium program. The negotiator then reportedly admitted to the existence of the program in somewhat cagey terms, and suggested uranium enrichment could be abandoned in exchange for the United States following through with other Framework preventions, such as the normalization of relations and removal of sanctions. (North Korea later claimed, incredibly and somewhat incoherently, that its negotiator had been mistranslated, and had only argued for its hypothetical right to uranium enrichment—which, by the way, was only for civilian purposes.)

This apparent belligerent admission led the Bush administration to cut off the fuel oil shipments. Within a few weeks, Pyongyang retaliated by announcing it was withdrawing from the Non-Proliferation Treaty and reclaiming nuclear fuel from the IAEA. KEDO was effectively nixed as well. Pyongyang’s nuclear-weapons program kicked back into full gear.