Introduction

Today, about 27 percent of America's active-component military is overseas - a proportion that equals more than 350,000 troops. The proportion of the force overseas today is 50 percent higher than the average for the period 1992-2002.

More than half of the troops that the United States currently maintains overseas are engaged in actual military operations, while the rest are stationed at permanent bases or completing routine overseas rotations. Not since the Vietnam war has so large a portion of America's active-component military been engaged in long-term military operations overseas. The average percent of the active force engaged in overseas military operations for the years 2003 and 2004 is more than five times the average for the years 1992-2002.

Only about 60 percent of American military personnel belong to warfighting units and are considered "expeditionary"; most of the rest constitute infrastructure support. Most of the troops stationed or deployed overseas belong to the expeditionary segment, and this implies that America currently has deployed overseas about 45 percent of its combat personnel. The percentage varies across services, however. For the Air Force and Navy, the percentage overseas is somewhat smaller; For the Marine Corps and Army, higher. Indeed, the portion of Army warfighters currently overseas exceeds 60 percent.

Turning to the National Guard and Reserves: the proportion of their available strength currently employed overseas is unprecedented since the Korean war. In September 2004 a total of 170,000 reserve component troops were on active duty. More than 75,000 of these were deployed overseas, mostly in Iraq and Afghanistan where they constituted approximately 40 percent of all deployed forces. These are not included in the numbers given above for active component forces deployed overseas.

Adding together the active- and reserve-component troops either deployed or stationed overseas yields a total of more than 420,000. About half of these are in or around Iraq, supporting the occupation. Prior to the Iraq war (but after 11 September 2001) the comparable active-plus-reserve total overseas was approximately 250,000.

All told, well over 400,000 reservists have been mobilized at one time or another for foreign or domestic duty since 11 September 2001. Most of these belong to the "selected reserves," which comprise units that regularly train together. Currently, America's selected reserves number approximately 880,000. Thus, about half of these reservists have been mobilized at one time or another during the past three years.

In order to maintain the current high level of overseas activity many of the previous guidelines and "rules of thumb" for limiting overseas deployments have been set aside. Thus, combat assignments for Army troops have been extended from six months to a year or more, and average time between deployments has been cut. Guard and reserve tours have been extended, too.

Generally speaking, service leaders have sought in the past to routinely deploy one-third or less of warfighting forces overseas at any one time, while permitting relatively brief and infrequent surges to higher levels, such as during Operation Desert Storm. (One-third of the fighting force equals about 20 percent of active personnel overall). This pacing was meant to sustain morale and ensure that training, repair, and modernization cycles could be completed. The point of such guidelines was to strike a balance between current and future requirements.

Recent practice raises the prospect of two types of problems: first, a near-term decline in force cohesion and combat effectiveness while the military is still engaged in current operations; and, second, a long period of force recovery after current operations conclude. During this strategic "reset period" the capacity for large-scale military operations would be lower -perhaps significantly lower - than it was during the pre-war period. According to the Chief of the British Defence Staff, Sir Michael Walker, Great Britain already faces the second of these problems. In March 2004 he reported to the House of Commons Defence Committee that "[w]e are unlikely to be able to get to large-scale [operations] much before the end of the decade, somewhere around 08 or 09." (Daily Telegraph, 25 March 2004).

Further complicating the present circumstance of America's armed forces is that, by some measures and assessments, the achievement of current objectives in Afghanistan and Iraq require even more personnel and units than are currently deployed there.

Charts, Tables, Reference Materials, and Discussion

Change in the Percentage of US Military Personnel Overseas, Stationed and Deployed

US Military Personnel Overseas 2002-2004

A Measure of Stress on Active Component Army Personnel 1994-2004

Mobilized National Guard and Reserve, October 2001 - September 2004

Reference Readings: The Effect of Recent Military Operations on America's Armed Forces

Discussion: "Stretched too thin? The Effect of Recent Military Operations on America's Armed Forces" with James Fallows (the Atlantic), Lawrence Korb (CDI), Pat Towell (CSBA), Col. Douglas Macgregor (USA, ret.), and Carl Conetta, moderator. Sponsored by Security Policy Working Group and hosted by Project on Defense Alternatives, at the Marriott Metro Center, Washington DC, 19 October 2004.

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