Countering the United States in Vietnam } 241
leader Lee Kuan Yew that the PRC had supplied US$10 billion to the DRV,
equivalent to $20 billion in current terms.^17
The PLA also constructed a large and well-defended fortress complex at
Yen Bai in northwest DRV on the main rail line and highway from China’s
Yunnan province to the Red River delta. Apparently intended as a territo-
rial redoubt for PAVN in the event of a US or South Vietnamese invasion
of the Red River delta, the complex ultimately included some 200 buildings
and a very large runway. It was well defended by anti-aircraft guns built into
caves in neighboring mountains.^18
The air war became a hot area of US-PRC confrontation. US aircraft
would occasionally enter PRC airspace, either in hot pursuit of DRV aircraft
or as a result of inability to turn swiftly enough after bombing targets in the
DRV. Initially, in January 1965, China’s CMC ordered that PLA aircraft not
attack US aircraft that intruded into Chinese airspace. Mao overruled that
order, however, and directed that intruding US aircraft should be attacked.^19
The PLA would occasionally scramble fighters to intercept US planes entering
China’s airspace. Between September 1965 and August 1967, Beijing claimed
to have shot down nine US planes in China’s air space. Beijing also claimed
that one PLA plane was shot down in Chinese airspace by a US warplane.^20
Most of the PLA troops killed while assisting Vietnam probably died by US
bombing. In other words, in the air war over North Vietnam, PLA soldiers
were killing Americans and were being killed in turn.
Defining the Limits of US Escalation
There were several key components of US strategy during 1964–1968 (i.e., the
period of Lyndon Johnson’s presidency). Large and heavily armed US ground
forces conducted aggressive offensive operations within South Vietnam
designed to find, fix, and destroy North Vietnamese and NLF main force
units. This destruction of insurgent military forces was supposed to shield
intensified national building and pacification efforts by the Republic of
Vietnam (RVN) in South Vietnam’s countryside. Beijing’s main role in this
regard seems to have been provision of large quantities of arms, ammunition,
and military equipment to the “revolutionary forces” in South Vietnam. US
strategy toward North Vietnam was to gradually and incrementally escalate
the level of US bombing to the “breaking point” at which the level of death
and destruction suffered by the North was too great, causing VWP leaders to
pull back from their effort to topple the Saigon regime and suspend infiltra-
tion along the trails. Beijing played a critical role in persuading the United
States to limit its bombing.
The ambassadorial talks in Warsaw underway since the aftermath of the
1954 Geneva Conference were the major venue for US-PRC communication