Page 102(The Bitter End)
Interdicting the highways, the Khmer Rouge eventually controlled all but two of them. The fact that only two reliable routes of supply into Phnom Penh remained-by air into Pochentong airfield or by ship or barge via the Mekong River and the South China Sea-meant the life of the Khmer Republic hung in the balance. In jeopardy were the government-controlled province capitals which were being resupplied by the numerous "fly anything, anywhere, anytime" airlines operating from Pochentong Airport. Flying supplies in Bird Air Company aircraft (a U.S. contract airline) through Pochentong not only added considerable cost to the supply process, but also significantly reduced the probability of delivery. Under these difficult conditions, the continued survival of the outlying towns was doubtful and, at best, extremely tentative. Day-to-day existence now depended upon Phnom Penh's air and river resupply system.6
Thus, almost by default, the Mekong River, always a significant part of Cambodia, took on even greater importance. Navigable year round by coastal steamer and barge from Phnom Penh to the South China Sea, the river became the country's lifeline. As the Communists sirenghtened their hold on the overland lines of communication, including the LOC linking Phnom Penh with the country's only seaport, Kompong Som, and with aviation support becoming more costly and inconsistent, the Mekong River became the only practical means of supplying the government forces and feeding the swollen population centers. Even rice grown in western Cambodia was supplied to Phnom Penh by way of the Mekong. Because the Communists controlled the highways, the Cambodians first shipped the rice to Thailand where it was loaded on ships bound for Phnom Penh.7
At least weekly in the South Vietnamese port of Vung Tau, Mekong convoys formed for the journey to the Cambodian capital. They were comprised of chartered coastal steamers and barges, laden with military supplies and civilian cargo of every variety. After a usually peaceful two-day journey through South Vietnam, they were met at the Cambodian border by Khmer Navy escort craft for the hazardous final day's steam to Phnom Penh. The FANK lacked the manpower to secure the 62 miles of riverbank stretching from the South Vietnamese border to Phnom Penh. It did, however, possess enough strength to provide sufficient strongpoints and fire bases along this dangerous portion of the waterway to enable them to deny the Khmer Rouge easy access to key chokepoints around river islands and narrows. The Cambodian Army reinforced this coverage with interlocking artillery fire.8
During the monsoon season the convoys were rarely threatened. The rains would inundate the foliaged river banks where the Khmer Rouge units always built their gun emplacements. As a consequence [he flooding effectively neutralized the Communists' 12.7mm machine guns and rocket-propelled grenade launchers (RPGs) for nearly six months out of the year.
The Communist dry season operations of 1973 were successful in periodically interdicting the lines of communication into Phnom Penh. For a short period, all supply routes were cut. In order to continue to block these lines, the Khmer Rouge had to mass its forces, and whenever the Communists did, they usually suffered heavy casualties. FANK counterattacks using U.S. close air support (until August 1973), effectively neutralized the massed Communist forces. Whether the same Khmer Rouge tactic of massing its forces would have worked in 1974 remains a matter of conjecture. The Communists in 1974 altered their tactics. Instead of concentrating their forces in an effort to break or block the lines of communication into Phnom Penh, the Khmer Rouge attempted to terrorize the capital with artillery fire and 107mm rockets, principally the latter. It appeared for a while that these attacks by fire against the civilian population would succeed. But once again the Cambodian Government confounded the experts and the capital held.9
That dry season came to a close in June 1974 with the Khmer Rouge still maintaining a tight stranglehold on Phnom Penh, but without a victory. By not attempting to block the river in 1974, the Khmer Rouge gave the Lon Noi government at least another year's longevity. An inference could be made that because of [he mauling the Khmer Rouge units received during the 1973 campaign, their manpower resources were insufficient to mount an offensive on the same scale in 1974. Regardless of the reason, the Cambodian republic had weathered another storm and the symbol of its strength, Phnom Penh, still housed the American Embassy and its staff.
The Khmer Communists' Last Dry Season Offensive
The Khmer Rouge opened their 1975 offensive on the last day of 1974. The Lon Noi government had expected a resumption of hostilities sometime in January of 1975 and the Communists did not disappoint them. The Khmer Rouge attack on 31 December seemed to be right on schedule. It immediately ex-
Page 102(The Bitter End)