Office of the Historian

150. Memorandum From the Chairman of the Joint Chiefs of Staff (Moorer) to Secretary of Defense Laird1

CM–1848–72
Washington, May 15, 1972.

SUBJ

  • Air Campaign in North Vietnam (U)
1.
This responds to your memorandum of 10 May 1972, which requested the Line Backer plan and information on certain related topics.
2.
The objectives of the air campaign (Line Backer) are to destroy and restrict the flow of war material through the North Vietnamese land mass and contiguous coastal waters by disrupting lines of communication and destroying transportation assets and supplies. The air campaign operates in concert with the mining operation (Pocket Money), which is designed to restrict the flow of maritime shipments into NVN.
3.

NVN depends entirely on imports to support its war machine. The transportation target system consists of elements of the military supply and distribution network through which these imports move to the battlefields in Laos, Cambodia, and most particularly RVN. These elements primarily consist of the principal choke points along the rail/highway LOC, the means of transportation (trucks, rolling stock, and water craft), the repair facilities for maintaining them, war supplies and war support materials, the ports, transshipment points, and supply points through which the imports move, and the other critical components throughout the NVN transportation system.

An initial priority effort is the reduction of existing POL stocks and the destruction of the major fixed POL storage facilities. The national POL storage capacity in fixed sites is 160,000 metric tons. Twenty-three principal POL targets represent more than 50 percent of this capacity, most of which is stored in underground tanks or dispersed sites which are difficult to dig out. The remaining POL stores are contained in some 250 fixed site facilities ranging downward from 700 metric ton capacity. In addition, there are innumerable transitory drum sites with an estimated capacity of 60,000 metric tons. These targets become less and less lucrative and more difficult to destroy as their size decreases.

4.
There are eight key bottlenecks along the Northeast and Northwest rail lines. Successful interdiction of these lines will complicate the North Vietnamese efforts to increase overland shipments now that their sea lanes are closed. They will be forced to use time-consuming shuttling operations and to divert rail shipments to the road network.
5.
Sealing off the ports was the first milestone. This move shut off maritime shipments which represent 95 percent of all imports. Rail shipments from China have been averaging 600 short tons per day. Imports will be limited to these quantities until the Soviet and Chinese increase their overland inputs. It will probably take the enemy several months to accommodate to the loss of his port facilities and the disruption of his principal overland lines of communication. Our primary effort in the early phases of Line Backer will be directed toward delaying this accommodation. If imports can be kept below the minimum required to sustain planned levels of combat and essential domestic functions, the enemy will have to draw down on his stockpiles. How long North Vietnam can continue the present combat level relates directly to our success in curtailing imports over an extended period.
6.

As indicated above, the successful mining operation is expected to create a gap in the flow of supplies that will reduce imports below essential minimums. The enemy is now faced with the enormous task of completely readjusting his supply and distribution system to handle increased rail shipments from China. It will take 4 to 6 months of uninterrupted effort for the enemy to complete the readjustment. Our interdiction campaign is aimed at keeping the supply line capacity from the Chinese border to the battlefield reduced to the lowest possible level.

Once the key bridges and choke points along the two rail lines and the principal highway alternates have been successfully interdicted, the campaign will continue at the reduced level necessary to maintain interdiction of these bottlenecks and to destroy and harass logistic traffic. Some strike forces can then be diverted back to the ancillary effort of reducing the enemy’s military capability and his war support facilities.

7.
The near-term results will be disruption of the military supply and distribution system. Over the long-term, we can expect the campaign will impact seriously on the enemy’s ability to maintain an adequate logistic network and will degrade his capability to support his supply lines in Laos by requiring diversion of trucks, repair assets, and AAA to cover the entire length of the logistic network. The cumulative effects of the interdiction campaign and the supplementary effort to reduce the North Vietnamese war-making capability should cause the enemy to lower the level of combat.
8.
Based on previous experiences, North Vietnam can be expected to resort to lighterage in attempts to accommodate to the mining and [Page 561] the air and NGFS attacks. The enemy will probably also focus immediate attention on developing alternate means of moving supplies, similar to methods he has employed in Laos. Our forces and tactics will require continuous adjustment based on the enemy’s efforts to accommodate to closure of the ports, and his ability to reconstitute his defenses and develop alternate LOC. As new targets are developed, they will be struck with available air assets and NGFS.
9.
The USSR and PRC can be expected to apply psychological and diplomatic pressure on behalf of North Vietnam. They will probably also take measures to continue the supply flow to North Vietnam by overland routes through China. I feel it is unlikely that either USSR or China will directly involve their combat forces in an offensive role. However, we are watching carefully for actions which indicate otherwise.
10.
Friendly loss rates are estimated at less than one half of one percent overall. The rate is expected to decline as the operations progress. Loss rates apply primarily to strike aircraft. A lower loss rate is estimated for support aircraft because they generally experience less exposure to active enemy defenses. Overall, the losses are considered acceptable in light of the significant objectives.
T.H. Moorer
  1. Source: Washington National Records Center, OSD Files: FRC 330–77–0095, 385.1, Viet (January–May 1972). Top Secret; Sensitive.↩