The 2018 summit between U.S. President Donald Trump and North Korean leader Kim Jong Un was the result of almost a decade's worth of discussions between the two countries, The Wall Street Journal reports.

Current and former officials at the Central Intelligence Agency confirmed to the Journal a channel existed between the two countries' intelligence agencies, and the CIA conducted two missions to Pyongyang in 2012, one by then-deputy director Michael Morell and one by his successor, Avril Haines. That channel apparently went dormant toward the end of the previous administration, but was revitalized under Mike Pompeo when he led the CIA.

This channel eventually played a role in the talks, both secret and public, to bring Trump and Kim together. It helped create relationships between various security personnel, including Gen. Kim Yong Chol, who formerly led the Reconnaissance General Bureau, which the Journal notes is a North Korean spy agency, and has since become the country's senior negotiator.

"The rationale for using a channel between intelligence agencies would be that in the event of some sort of crisis it could provide a capability to reach people in their system with authority," said former Obama Administration official Daniel Russel, who worked for the State Department and the National Security Council official. "Generally speaking, in countries like North Korea, the foreign ministry has limited influence, so you need to be able to speak to the guys with the guns."

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