7. The Risk of Chinese Intervention Led to the Shelving of the Plan to Invade North Vietnam
The plan to invade the Haiphong-Hanoi area stood a high chance of success against the North Vietnamese. However, it was deemed too dangerous because there was no guarantee that the invaders would only have to deal with North Vietnamese forces: the odds that China would join the fray were high. At the time, only 15 years had gone by since the Korean War. In that war, US and allied forces had pursued the routed North Koreans all the way to the Chinese border, based on the mistaken belief that China would do nothing. That led to an unpleasant surprise when the Chinese jumped in and pushed American forces all the way back to South Korea.
If China directly joined the Vietnam War in response to a US invasion of North Vietnam, things could easily escalate from there into WWIII, and drag in the Soviets. Unlike the situation during the Korean conflict and in the early days of the Cold War, the US no longer held an overwhelming nuclear superiority. By the second half of the 1960s, the Soviets possessed thousands of nuclear warheads, as well as the means to deliver them to targets in the US. American interests in Vietnam were simply not worth the risk, and the so the planned invasion of Hanoi-Haiphong was never carried out.
