On April 20, 1967, the United States escalated its air campaign by striking Haiphong, North Vietnam’s largest port and second-largest city. A force of 86 American planes attacked fuel storage sites and logistical facilities, aiming to disrupt the flow of supplies entering the country. Haiphong had long been considered off-limits because of the danger of striking foreign vessels docked in its harbor—ships from the Soviet Union, China, and other countries that were supplying North Vietnam with vital materials. The decision to bomb the port marked a major turning point in Operation Rolling Thunder, signaling that Washington was prepared to risk diplomatic fallout in order to expand its pressure on Hanoi.

The raid was both militarily significant and politically risky. Haiphong was the critical entry point for much of North Vietnam’s war supplies, and destroying storage depots there struck directly at the North’s ability to sustain the conflict. At the same time, the attack increased the danger of direct confrontation with America’s Cold War rivals, who viewed Haiphong as a lifeline for their ally. While the bombing inflicted serious damage, it also reinforced Hanoi’s determination to continue fighting and deepened international criticism of U.S. escalation. The strike on April 20 demonstrated both the reach of American air power and the widening risks of the war.