Operation Pocket Money: Nixon Cuts Off Soviet Supplies
In early May 1972, as the U.S. Navy began to mine Haiphong harbor, President Richard Nixon appeared on television to address the nation. He opened his remarks as follows:
Five weeks ago, on Easter weekend, the Communist armies of North Vietnam launched a massive invasion of South Vietnam, an invasion that was made possible by tanks, artillery, and other advanced offensive weapons supplied to Hanoi by the Soviet Union and other Communist nations.
In sharp contrast with the 1968 Tet Offensive, North Vietnam's Nguyen Hue Offensive was a conventional invasion led by armored forces and tanks. This was made possible by the provision of modern arms, for free, by the Union of Soviet Socialist Republics.
The majority of North Vietnam’s war expenses were paid for by the Soviet Union. China also chipped in, although this steadily diminished as President Richard Nixon's rapprochement with China gained momentum. From 1965 through 1968 the overwhelming majority of assistance from the USSR was for the construction of an extensive North Vietnamese air defense system. Soviet military aid dropped off when the U.S. ceased bombing North Vietnam in November 1968, but it began to pick up sharply in 1971 and continued to increase steadily in 1972. Much of the new military assistance was in the form of armored fighting vehicles.
A 1969 U.S. National Security Study cited the Department of State as saying that about 85 percent of Communist aid to the Democratic Republic of Vietnam arrived by sea, with rail deliveries from China account for the remaining 15 percent. Most of those sea shipments arrived at the port of Haiphong, North Vietnam's only major seaport.
The 1972 Nguyen Hue Offensive
The Nguyen Hue Offensive, alternatively known as the Easter Offensive, was the largest ground operation since the Korean War, when 300,000 Chinese soldiers crossed the Yalu River into North Korea. According to Vietnam's Ministry of National Defense, North Vietnam dedicated a force of about 10 battalions, which were equipped with 322 tanks and armored vehicles. Most of those tanks were either Soviet T-34 medium tanks of Second World War vintage, Soviet T-54 main battle tanks from the post-WWII era and Type 59s, which were Chinese-manufactured versions of the Soviet T-54A.
By fielding a relatively modern army equipped with tanks, long-range artillery and air defense weapons, the People's Army of Vietnam had created a significant vulnerability for themselves. They were now heavily dependent on a large-scale, continuous supply of replacements, gasoline and ammunition. Interdiction of Haiphong harbor and rail lines from China would, over time, prevent Hanoi from receiving supplies required to continue the war effort.
Operation Pocket Money
In his televised address to the nation, Nixon continued:
All entrances to North Vietnamese ports will be mined to prevent access to these ports and North Vietnamese naval operations from these ports.
United States forces have been directed to take appropriate measures within the internal and claimed territorial waters of North Vietnam to interdict the delivery of any supplies.
Rail and all other communications will be cut off to the maximum extent possible. Air and naval strikes against military targets in North Vietnam will continue.
Until then, naval mining at Haiphong had often been a topic for consideration but it was always rejected, due to the risk of inciting a larger conflict involving Russia or China. On May 9, 1972 (Vietnamese time), a U.S. Navy Seventh Fleet aircraft carrier strike force began to mine Haiphong harbor by air, in an operation code-named Pocket Money. Moscow and Beijing both denounced the U.S. action. Each one was unwilling to jeopardize their own thawing relations with the United States and was wary of their rival's dealings with America. No military response was provoked.