TLDR: A conspiracy theory that South Korea and North Korea worked together to prevent a popular South Korean politician from being elected president was actually proven to be true.

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In 1990s South Korea, there was a suspicion that there was some funny business going on to prevent a guy named Kim Dae-jung from being elected as president. Basically, he was a left-leaning politician who favoured a more reconciliatory tone towards North Korea.

South Koreans in charge obviously didn't like that. But surprisingly to some, neither did the North Koreans in charge. To legitimize their power, North Korea needed a South Korean enemy to fight against. Kim Dae-jung's friendlier approach would threaten that.

So South Korean and North Korean officials cooked up a scheme. They met secretly in China, where South Korea gave money to North Korea to create border disruptions whenever Kim Dae-jung got too popular during election campaigns.

This became so routine that South Korean citizens nicknamed it the "North Wind." It was a conspiracy theory that North Korea would do something to sabotage Kim Dae-jung whenever he got too popular.

Eventually a South Korean spy blew it wide open. He was posing as a businessman from South Korea who was interested in filming advertisements in the North, meeting North Korean officials in China. In reality, he was working for South Korean intelligence to gather proof and details of North Korea's nuclear program.

During one of those stays in China, he happened to be in the same hotel and proximity to the North and South Koreans in the scheme and confirmed the scheme's existence with his North Korean colleagues. He gathered enough proof of what was happening to threaten to go public, if they kept going with it. They didn't and without the "North Wind," it resulted in Kim Dae-jung winning the election.

Kim Dae-jung eventually became known as South Korea's greatest president and won the Nobel Peace Prize for his North Korea strategy.

This whole thing was dramatized in the film [The Spy Gone North](https://en.wikipedia.org/wiki/The_Spy_Gone_North). If you want to Google more, the spy's code name was "Black Venus." None of this was publicly known until around the 2000s to 2010s, when the people involved were convicted.