A man watches a television screen showing a news broadcast on North Korea's nuclear test at Seoul Station in Seoul, South Korea, on Wednesday, Jan. 6, 2015. North Korea claimed that it successfully tested its first hydrogen bomb, the fourth time it has detonated a nuclear device and a move that reignites tensions with neighbors including China after months of calm. Photographer: SeongJoon Cho/Bloomberg

North Korea has conducted nuclear tests before, but the nuclear test the country carried out Wednesday could be dramatically different. According to Pyongyang, the device tested was a hydrogen bomb – a type of device that produces a considerably more powerful blast than the previous devices tested. South Korean officials and a number of nuclear experts have cast doubt on the claim, pointing out that the yield recorded in the test seemed to be similar to the previous tests conducted by North Korea.

Despite the doubts, the unexpected nuclear test is yet another reminder of how the U.S.-led nuclear deal with North Korea, brokered under President Bill Clinton in 1994, failed. Isolated, embattled North Korea is the only country to test nuclear weapons in almost 20 years, and it shows no signs of slowing down. Given the controversy surrounding a recent nuclear agreement reached with Iran, it's worth considering exactly how the deal to stop its nuclear ambitions fell apart.

North Korea's plans for nuclear weapons are believed to date back to at least the 1960s, when it began to ask the Soviet Union – at the time its most vital ally – for help to develop the weapons. Moscow repeatedly rebuffed the requests and privately pushed North Korea to join the nuclear Non-Proliferation Treaty, an international agreement designed to limit the spread of nuclear weapons.

North Korea eventually joined the NPT in 1985, but it did not come to a safeguards agreement with the International Atomic Energy Agency (IAEA), justifying its inaction by pointing out that the United States kept nuclear weapons on the southern part of the Korean Peninsula. After nuclear weapons were withdrawn from South Korea in 1991 (part of a unilateral U.S. decision to destroy nuclear warheads designed for short-term use and move nuclear weapons kept on-board warships that was swiftly reciprocated by a Soviet one), North Korea reached an agreement with the IAEA.

The IAEA quickly ran into trouble in North Korea over site inspections in the country, however, convincing many experts that Pyongyang was still trying to produce a nuclear weapon. Tension mounted, and in 1994 North Korea announced its withdrawal from the IAEA agreement and said it intended to withdraw from the NPT.

Clinton helped spearhead a new deal later that year. In what was dubbed the Agreed Framework, North Korea committed to freezing and eventually dismantling its nuclear weapons program in exchange for two nuclear power plants (built with proliferation-resistant, light water reactors) fuel oil and a commitment to easing sanctions and normalizing relations. The deal was portrayed as a turning point at the time.

"This agreement is good for the United States, good for our allies, and good for the safety of the entire world," Clinton said. "It reduces the danger of the threat of nuclear [proliferation] in the region. It's a crucial step toward drawing North Korea into the global community."

The program caused considerable controversy within the United States, however; much like President Obama's Iran deal, it was structured as an executive agreement and thus did not require approval from Congress. This political dispute led to difficulty in funding the provisions of the agreement and easing sanctions. Many skeptics remained convinced that North Korea was still trying to covertly build a nuclear weapons program, and there were a number of disputes with Pyongyang over its continued missile programs.

After North Korea's claim that it tested a hydrogen bomb, The Post's Karen DeYoung explains why the U.S. response to the rogue nation is so different from how it treats Iran. (Jason Aldag,Gillian Brockell/The Washington Post)

When George W. Bush succeeded Clinton as president in 2001, he sought to take a harder stance on North Korea. In 2002, the United States confronted North Korea with evidence that it had been pursuing a secret uranium-enrichment program. North Korea apparently confirmed this in a meeting with an envoy, prompting the United States to withdraw its supply of fuel oil. The Agreed Framework broke down, and North Korea restarted its nuclear weapons program.

Subsequent attempts at further talks with North Korea have failed – the Bush administration even attempted a deal that saw sanctions lifted and North Korea removed the from the U.S. list of state sponsors of terrorism, but it collapsed before Bush left office. North Korea conducted its first nuclear test in 2006. The test this week would be its fourth. It is currently believed to possess around 10 to 16 nuclear weapons, though exact estimates vary considerably.

Critics of the Obama administration have argued that the failure of the nuclear agreement with North Korea carries lessons for the recent deal with Iran. Marc Thiessen, a columnist for The Washington Post, argued that the agreement reached with Iran was "actually worse" than the deal Clinton reached with North Korea. "Korea had to cheat on its deal to break out as a nuclear power," Thiessen wrote. "Iran does not have to cheat." Tom Cotton, a Republican senator from Arkansas, has also cited the failure of the North Korea deal as a reason for opposing  the Iran deal.

Others disagree. The Carnegie Endowment's George Perkovich, for example, has argued that Iran has stronger incentives to stick to a deal than North Korea ever did and that it was ultimately North Korea's relative weakness and insecurity that led it to seek nuclear weapons. The Post's Glenn Kessler has noted that under a different administration, there may have been more political will to keep the agreement going and use its provisions to apply leverage to North Korea.

What isn't in doubt is that the deal failed – and that there's been little sign of a detente ever since. After each of North Korea's nuclear tests in 2006, 2009 and 2013, as well as a satellite launch in 2012, the United Nations Security Council has adopted resolutions that imposed sanctions on North Korea and attempted to restrict its access to the equipment needed for a nuclear weapon program. Pyongyang has shown no sign of de-escalating the situation, howeve. Aside from this week's nuclear test, the country has also claimed to have developed a nuclear warhead small enough to fit on a missile.

Officially, North Korea is saying it has no desire to seek a similar deal to the one offered to Iran. North Korea "is not interested at all in the dialogue to discuss the issue of making it freeze or dismantle its nukes unilaterally first,” a Foreign Ministry spokesman said in July, according to the state-run Korean Central News Agency.

More on WorldViews

Saudi Prince Bandar: The U.S. nuclear pact with North Korea failed. The Iran deal is worse.

This journalist didn’t just interview North Korean defectors, he followed them on their escape

North Korea has threatened a U.S. attack for years. Why aren’t you scared?

Correction: In the original text, this post incorrectly described the 1991 presidential nuclear initiatives as withdrawing all nuclear weapons left overseas. It has been amended.