91. Memorandum From Secretary of Defense Brown to President Carter1


  • U.S. Military Utilization of the Panama Canal

This memorandum provides a brief description of the Department of Defense’s past use of the Panama Canal and the canal’s potential impact on defense planning for various conflict scenarios.

United States’s military use of the Panama Canal has two broad strategic aspects:

—Interoceanic transfer of warships and their supporting auxiliaries.

—Logistical support (movement of supplies and equipment) for U.S. and allied forces in Europe and the Pacific.

A review of historical data shows that during a nine year period of the Vietnam conflict, 1964–1972, the canal averaged 123 warship and 645 military logistical transits (about four million tons of military cargo) per year. For the four year period between 1973–1976, the averages for warship and logistical transits were reduced approximately two-thirds to 42 and 219 (about one million tons of military cargo) respectively. During the peak 1967–1969 period, approximately 49 percent of all US Government cargo arriving in Vietnam passed through the canal. The highest this figure ever reached was in FY 1968 when 69% of this type of cargo passed through the canal. These figures represent all naval ship transfers between the Atlantic and Pacific fleets. The largest naval transit was the 39,000 ton amphibious assault ship USS TARAWA in [Page 272] 1976. Tab A provides a detailed breakout of US Government ship passages from fiscal year 1964 to 1976.2

Our planned wartime and contingency use of the canal (Tab B provides details and is classified SECRET)3 is based on a strategy which permits rapid augmentation of forces in the Atlantic or Pacific theaters. Canal use improves availability of surface escorts, amphibious shipping, and logistical support. Its use reduces transit times and this equates to increased defense force availability in the early period of a conflict. Current planning reflects programmed use of the canal; however, alternate routes and measures are part of military planning in the event the United States is denied its use. Attack carriers and their escorts already use routes such as those around Africa and South America although this adds an average of 15–21 days to their transit time.

In a NATO conflict, significant numbers of cruisers, destroyers, frigates, and a substantial portion of amphibious lift for Marine Corps forces would transit the canal. This would reduce the time to achieve availability by 15 to 21 days for the Atlantic-Mediterranean theaters when compared to ship transits which did not use the canal. The canal also assists in the movement of military cargo from West Coast ports and facilitates the assembly of shipping in the Atlantic. The use of the canal results in a net increase in cargo capacity of 30 percent during the first month of mobilization.

The escort requirements are not as significant in a Pacific only scenario. However, because of West Coast port limitations (safety and capacity), current plans require approximately 75 percent of certain critical cargo to be shipped from the East Coast during the first thirty days of a conflict in the Pacific. During the 60-day initial period, use of the canal facilitates assembly of shipping and improves delivery of critical cargo by 18–25 percent. The canal also reduces the time required to assemble amphibious shipping by approximately 30 percent. Tab B provides a classified examination of the effect of canal closure on operation plans.

The paper does not address long term alternatives which might be undertaken to compensate partially for the unavailability of the canal. In sum, assured ability to transit the canal remains of military importance, though rather less than in the past. Therefore, the principal military interest is to assure that ability. I agree with the JCS that the proposed canal treaties are the best way to do so.

Harold Brown
  1. Source: Washington National Records Center, 1977 Country Files: FRC 330–80–0035, Panama Canal 1977 000.1—091.31. Secret.
  2. Attached but not printed.
  3. Attached but not printed.