Numerical Considerations in Military Occupations

By Brig. Gen. John S. Brown, U.S. Army retired

A frequent criticism of current operations in Iraq is that we committed too few troops to the tasks of occupation. How many troops should we have committed? Gen. Eric K. Shinseki’s prewar forecast that we would need several hundred thousand is now iconic, albeit unspecific. A recent RAND study suggests one soldier to 50 people is about right—thus occupying a nation of 23 million would require about 460,000 soldiers. Unfortunately, our own history does not inspire much confidence in such mathematics. In 1946 we fielded one soldier for every 500 (and a few years later one for every thousand) Japanese during an occupation so successful it converted a ferocious adversary into a staunch ally. During that portion of the Vietnam War that resembled an occupation, we fielded almost one allied soldier for every 10 Vietnamese, and nevertheless came to an unhappy result.

Each occupation is unique. The collateral missions associated with each are unique as well. An occupation may solely intend to enforce the instrument ending hostilities or to achieve a stated objective. Examples include our participation in the occupation of the Rhineland after World War I, or of southern Iraq in 1991. The occupation of the Rhineland held critical portions of Germany hostage to coerce the Germans to adhere to the armistice and accept the Treaty of Versailles. Americans poured 260,000 troops into a tiny sector with 900,000 souls, including Trier and Coblenz. The ratio of troops to population was never an issue, since no attempt was made to occupy Germany as a whole. Similarly, in 1991 we maintained 150,000 soldiers in a portion of Iraq that had few people and much oil until Saddam Hussein complied with our terms. Such coercion implies an effective residual government worth coercing. In its absence, such collateral missions as humanitarian relief, law and order, nation building or external defense may drive required numbers up.

War can create huge numbers of distressed individuals, and an occupying power is generally responsible for them until someone else takes over. In Austria after World War II, Americans were generally accepted as liberators, but nevertheless found their hands full with 186,000 displaced persons and 305,000 prisoners of war. In Germany we dealt with 550,000 displaced persons and 2,000,000 ethnic Germans fleeing the Soviets. In Japan 1, 200,000 displaced persons (generally imported foreign labor) were trying to get out while 6,600,000 Japanese overseas were trying to get back. Occupations of Bosnia beginning in 1995 and Kosovo beginning in 1999 repeated this pattern, with hundred of thousands of refugees having fled the fighting.

Law and order can break down during the course of hostilities, or perhaps not be present in the first place. Occupations of Haiti (1915-1934) and Nicaragua (1926-1933) intended to secure American lives, property and interests until local constabularies could be raised to do the same. The Philippines (1899-1916), Italy (1943-1945) and Korea (1945-1948) similarly suffered lawlessness. In Bosnia and Kosovo it proved difficult to distinguish crime from violence for other purposes, and Kuwait (1991) had to recover from crimes so systematic they amounted to rape.

Occupied nations often have to be built or rebuilt to achieve our vision for their future. In Japan the grip of traditional elites was shaken by land reforms involving half the labor force and redistributing one third of the land. Germany, Italy and Austria were beneficiaries of the Marshall Plan. The Philippines proved an opportunity for our progressive movement to express itself overseas. Kuwait, Bosnia and Kosovo also witnessed major post-war relief efforts.

Occupying powers can find themselves responsible for security from external threats. In post-World War II Germany, Austria, Italy, Japan and Korea, we found ourselves facing threats from the Soviets and their communist allies. A fraction of the logic for inter-war occupations in Haiti and Nicaragua was to pre-empt European powers from believing they needed to intervene on the behalf of their own nationals. By 1916 American units in the Philippines focused on external threats while Filipinos handled internal security. Troops in Bosnia and Kosovo kept a wary eye on Serbia, whereas in Kuwait they confronted Iraq. In Vietnam our adversaries controlled the pace of the war from cross-border sanctuaries and repeatedly forced us to shift focus between internal stability and external threat.

With so many variable missions involved, it should not surprise us that nations rarely forecast the numbers an occupation will require accurately—except perhaps in cases of coercive diplomacy. Within a given occupation, numbers can fluctuate wildly until a solution that works sorts out. In Japan and Italy we ultimately settled on about one soldier for a thousand in the population. In Nicaragua one in 200 worked. In the Philippines, Haiti, Germany and Austria, numbers were closer to one in a hundred, and in Korea, Bosnia and Kosovo closer to one in 50. One in a hundred might make a reasonable rule of the thumb, but realistic assessments of collateral missions, open-mindedness and flexibility seem essential to success as well.

How will Iraq fit this pattern? We were determined upon regime change, so another coercive occupation of their oil fields was out. To our credit, we fought carefully enough that customary humanitarian crises with waves of refugees never occurred. Law and order did break down, and we faced a huge crime problem and a modest, albeit generally local insurgency. We assumed a nation building role, with uneven success thus far. We did not face a serious external adversary, but long porous borders greatly aggravate security issues. Through all of this our troop strength has been well shy of the one in a hundred “average” of our past, which lends all that much more urgency to the pace with which we refurbish Iraqi forces. We seem to be gambling that our soldiers are so good, our leadership so thoughtful, and our objectives so agreeable to the general Iraqi population that we will achieve acceptable results despite the thinness of our numbers. Let’s hope we are right.

Recommended Reading:
Birtle, Andrew J. U.S. Army Counterinsurgency and Contingency Operations Doctrine, 1860-1941 (Washington, D.C.: Center of Military History, 1998)

Finn, Richard B. Winners in Peace: MacArthur, Yoshida, and Postwar Japan (Berkeley, Calif.: University of California Press, 1992)

Linn, Brian M. The Philippine War, 1899-1902 (Lawrence, Kan.: University Press of Kansas, 2000)

Stewart, Richard W., General Editor. American Military History: the United States Army in a Global Era, 1917-2003 (Washington, D.C.: Center of Military History, 2005)

Ziemke, Earl F. The U. S. Army in the Occupation of Germany, 1944-1946 (Washington, D.C.: Center of Military History, 1975)