The North Koreans have been provoking the United States for as long as North Koreans have been praising Kim Il-Sung for being birthed from a shooting star.
In the 1960's the Hermit Kingdom was at the height of its power, which mostly came from the Soviet Union, who both supplied it and protected it from U.S. "intervention."
The election of U.S. President Richard Nixon changed how Communist nations interacted with the United States in geopolitical affairs. Nixon, a staunch anti-Communist Cold Warrior, was able to provoke the major Communist powers and them off of one another. His famous 1972 trip to China and the subsequent thaw in relations with the USSR are proof that Nixon's "triangulation" theory had merit.
But in April 1969, mere months into the first Nixon Administration, Nixon's internationalist savvy was still unproven. That's when North Korea shot down an EC-121 spy plane over the Sea of Japan. Nixon was furious.
A July 2010 story on NPR featured remarks from Bruce Charles, an Air Force pilot based in Kunsan, South Korea at the time. He recalled being put on alert to carry out his part of the SIOP, the Single Integrated Operational Plan – the U.S. nuclear strike plan for war with the Communists.
Charles was put on alert to drop a 330-kiloton nuke on a North Korean airstrip.
Eventually, the order to stand down was given, and Charles returned to his regular duties. According to the official accounts, Nixon and his advisors mulled over how to respond. In the end, the President opted not to retaliate.
It's worth speculating that Nixon would have wanted the Communists to believe he actually considered a nuclear strike. In the coming years, the President would even send nuclear-armed bombers toward the Soviet Union while spreading the rumor that he was so insane, he might really trigger World War III.
Of course, he wasn't insane. And thanks to a 2000 book by Anthony Summers and Robbyn Swan, we know he was just drunk. Not with power, but with booze.
George Carver, a CIA Vietnam specialist at the time of the EC-121 shootdown, is reported to have said that Nixon became "incensed" when he found out about the EC-121. The President got on the phone with the Joint Chiefs of Staff and ordered plans for a tactical nuclear strike and recommendations for targets.
Henry Kissinger, National Security Advisor for Nixon at the time, also got on the phone to the Joint Chiefs and got them to agree to stand down on that order until Nixon woke up sober the next morning.
According to Summers and Swan's book "The Arrogance Of Power: The Secret World Of Richard Nixon," Kissinger is reported to have told aides on multiple occasions that if the President had his way, there would have been a new nuclear war every week.