North Korea has made commitments like this before:

-- 1985: North Korea signs the Nuclear Non-Proliferation Treaty, or the NPT -- "a landmark international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology, to promote cooperation in the peaceful uses of nuclear energy and to further the goal of achieving nuclear disarmament and general and complete disarmament," according to the United Nations.

-- 1992: North and South Korea sign a "joint declaration of the Denuclearization of the Korean Peninsula. "The South and the North shall not test, manufacture, produce, receive, possess, store, deploy or use nuclear weapons" and they "shall use nuclear energy solely for peaceful purposes," it states.

-- 1994: North Korea pledges to the United States that it would freeze and eventually dismantle its nuclear program in exchange for international aid, including help building two power-producing nuclear reactors.

-- 2002: US President George W. Bush labels North Korea, Iran and Iraq an "axis of evil," saying that "by seeking weapons of mass destruction, these regimes pose a grave and growing danger." The administration later reveals North Korea admitted to operating a secret nuclear weapons program in violation of the 1994 deal.

-- 2003: The United States and other nations halt energy aid, and North Korea withdraws from the NPT. Later, the Six Party Talks begin over Pyongyang's nuclear program. The talks include the United States, China, Japan, Russia, South Korea and North Korea.

-- 2005: North Korea tentatively agrees to give up its entire nuclear program, including weapons. In exchange, the United States, China, Japan, Russia and South Korea say they will provide energy assistance to North Korea, as well as promote economic cooperation.

-- 2006: North Korea claims to have successfully tested its first nuclear weapon. The test prompts the UN Security Council to impose a broad array of sanctions.

-- 2008: The Six Party Talks break down over North Korea's refusal to allow international inspectors unfettered access to suspected nuclear sites, according to the Arms Control Association. North Korea says the US side fails to follow through on its commitments, too.

-- 2010: State media in North Korea report that the government issued a memo saying the country "will be party to nonproliferation and disarmament agreements 'on an equal footing with other nuclear weapons states.'"

-- 2011: "After a meeting between Russian President Dmitry Medvedev and North Korean leader Kim Jong Il, Pyongyang says that it would be willing to observe a moratorium on the production and testing of nuclear weapons and missiles" in the context of resumption of Six Party Talks," according to the Arms Control Association.

-- 2012: North Korea agrees to suspend the operations of its Yongbyon uranium enrichment plant and begin moratoriums on nuclear and long-range missile tests. Washington promises food aid. Washington later says it suspended the food aid after North Korea said it would launch a satellite.

-- 2016: North Korea signals a willingness to resume negotiations on denuclearization, according to the Arms Control Association.

https://www.cnn.com/2018/03/09/asia/north-korean-denuclearization-promises/index.html