Of Troops -- and the Truth

President Bush conceded recently that bringing stability to Iraq will take time -- and manpower. And the commander of allied forces in Iraq, Gen. John P. Abizaid, noted last week that American troops might well be required to serve yearlong tours of duty in Iraq, or double the usual length of time. These acknowledgements are a good start, but the administration has yet to answer one simple question: How many troops will be needed to bring that country under control? The American public -- as well as tens of thousands of military families -- deserves to know.

Even before the war was launched, the issue of postwar deployment numbers was controversial. On Feb. 25, then-Army Chief of Staff Eric K. Shinseki told Congress that “several hundred thousand” troops would be needed to secure postwar Iraq. Deputy Defense Secretary Paul D. Wolfowitz took sharp exception to Shinseki’s estimate, calling it “wildly off the mark.” But as conditions in Iraq have continued to deteriorate, often due to a lack of manpower and resources, the deployment question has resurfaced with a vengeance.

It’s clear that things are deteriorating in Iraq. Between June 9 and 22, the Pentagon logged 131 “incidents” involving U.S. troops there, including 41 attacks on U.S. compounds, 26 attacks on sentry or observation posts, and 26 on convoys. The next 24-hour period saw an additional 25 incidents. And the pattern of violence continues unabated.

Considering these circumstances, how might appropriate deployment numbers be calculated? Traditional military doctrine estimates that a conventional army requires a 10-to-1 size advantage to defeat a persistent insurgency. But it is not clear that this method is relevant for calculating numbers in the current situation, in part because the size of the insurgent force is unknown. More recent scholarship offers an alternate approach.

Military analyst James Quinlivan, writing nearly 10 years ago in the Army War College’s quarterly, Parameters, suggested that force requirements should be based on the need for both population control and local security. In other words, the deployment needs to be large enough to “win hearts and minds,” which requires a force proportional to the population as a whole.

So what’s an appropriate force ratio? Quinlivan looked historically at what kinds of force it took in different situations, and his analysis may have relevance for today’s situation. For ordinary policing, he estimated a need of between one and four security personnel per 1,000 population. The U.S. Constabulary force in post-World War II Germany, for example, was staffed at a little more than two troops per thousand individuals in the population. Its responsibilities there included enforcing public order, combating black markets and performing other police functions. But the force faced no organized guerrillas.

In more volatile situations, Quinlivan estimated a need for four to 10 troops per thousand in the population. When the U.S. intervened in the Dominican Republic in 1965, aiming to prevent civil war and restore order in a highly unstable situation, it used a force ratio of six security personnel per 1,000 population.

In situations that are even more volatile, the ratio goes higher still. In Northern Ireland during the height of the unrest, the British and the Royal Ulster Constabulary employed more than 10 security personnel per 1,000 population, and at times as many as 20. The situation they encountered there is much like what the Americans are seeing in Iraq today, with organized resistance intent on ousting “occupying” security forces.

So how do these various ratios translate to our presence in Iraq? If we took the German model as our guide, then something like 50,000 troops would be required to maintain order. But Germany was an utterly defeated, broken country where the main task was maintaining public order. Iraq is still a country at war, saturated with weapons and becoming more and more restless under the occupation. So a two per thousand ratio is unlikely to suffice.

A ratio of six per 1,000 population, as was deployed in the Dominican Republic, would require nearly 150,000 troops -- or roughly the number the U.S. and its allies have in Iraq today. Judging by our inability to restore order or to isolate militants intent on engaging U.S. troops, this force level seems inadequate.

To match the British ratio in Northern Ireland of 10 to 20 soldiers per 1,000 population, deployment numbers would skyrocket to between 240,000 and 480,000. The latter number is the total authorized strength of the active U.S. Army and would clearly be impossible to sustain considering that the equivalent of five of the Army’s 10 active divisions already are engaged in Iraq.

Whatever the numbers, Americans deserve an open discussion of these issues. The notion of achieving “peace through war” is a murky one. But now that we have waged war, we have a responsibility to restore peace. And that demands a discussion of how many troops we need to commit.