Since December 1995, the United States has deployed military forces in and around Bosnia to assist in implementing the Dayton Peace Accords. U.S. forces are part of a multilateral coalition under the command of NATO. From December 1995 to December 1996, the coalition was called the Implementation Force (IFOR). In December 1996, NATO authorized a new mission and renamed the coalition the Stabilization Force (SFOR). That mission was scheduled to end in June 1998 but has since been extended indefinitely. In voting to continue the mission, the North Atlantic Council retained the name SFOR. The Council stated that the extent of support over time will be adapted to developments in the political and security situation and to progress in the implementation of the civilian elements of the accords. Force levels will be reviewed at regular intervals. The United States has been a major force provider to the mission, as shown in table 1. The SFOR level will likely remain at 31,000, but the United States is seeking to reduce its troop commitment in Bosnia to 6,900. The United States plans to continue basing about 3,400 troops in neighboring countries. If the President determines that it is necessary to augment the active forces for an operational mission, he may use PSRC authority, which allows for the activation of up to 200,000 reservists at any one time, with each reservist limited to no more than 270 days of involuntary service. In December 1995, the President invoked this authority for the Bosnia mission. USAREUR is the major Army command primarily responsible for providing people for the Bosnia mission. Because USAREUR units are assigned fewer personnel than they are authorized, deployed units were augmented with personnel from other European units and active and reserve forces from the United States. At the same time, the relatively small size of the U.S. force in Bosnia required the Army to deploy partial units. USAFE is the principal Air Force command providing people for the mission. The Air Force’s personnel requirements are much smaller and the nature of the Air Force’s responsibilities allows for extensive use of reserve component volunteers. Almost 16,000 Army reservists and about 10,000 Air Force Air Reserve Component members have participated in the Bosnia mission between its inception in December 1995 and January 1998. Most of the Army reservists were involuntarily called to active duty under PSRC, whereas most Air Force reservists volunteered to participate in the Bosnia mission. Reserve units have participated because some required support capabilities reside primarily or solely in the reserves. For example, most of the Army’s movement control teams, civil affairs units, and fire fighter detachments are in the reserves. Of the 36 civil affairs units in the Army, only 1 is in the active force. The remainder are in the Army reserve. Reserve units also have been used to reduce the high level of activity of some active forces. For example, the Army uses reserve military police to relieve the high personnel tempo of active-duty military police units, and the Air Force uses reserve aircrews to relieve the high personnel tempo of its active-duty aircrews. Augmentation from reserve forces and U.S.-based active forces was required because USAREUR did not possess all the personnel and capabilities the mission needs. According to USAREUR documents, prior to the first deployment to Bosnia in December 1995, the units chosen to deploy were staffed at 87 percent of required strength, whereas deployed forces were required to be at least at 92 percent of required strength. Further, 8 to 10 percent of these units’ personnel were not deployable for a variety of reasons. To bring these units to at least 92 percent of required strength, personnel had to be shifted from other USAREUR units and from U.S. Army Forces Command (FORSCOM) units, a process known as cross-leveling. Throughout the Bosnia mission, individuals have been needed to augment headquarters staffs at USAREUR, U.S. European Command, the American contingent of various NATO command elements such as the SFOR Headquarters in Saravejo, and actual units. FORSCOM provided 1,035 active component individual augmentees to support Bosnia, while the Army Reserve Personnel Center and the U.S. Army Reserve Command provided another 1,613 Army Reserve individual augmentees. The relatively small size of the U.S. portion of SFOR has not always required deploying entire units. According to FORSCOM and USAREUR officials, active units have employed split-based operations. Split-based operations occur when only parts of units are deployed and the elements left behind must continue to perform their missions at the home station. For example, as of January 1998, elements of the First Armor Division’s headquarters, military intelligence, signal, artillery, and support command were deployed to Bosnia, while the rest of the division, including its combat brigades, did not deploy. Split-basing has been a strain on USAREUR units. For example, during SFOR, USAREUR reported to the Department of the Army through its Status of Resources and Training System, which is used to measure readiness, that split-basing had a negative impact on the readiness of several of its units because of reduced personnel, equipment levels, or a combination of both factors at home station. For reserve units, the Army also has engaged in split-based operations. In many instances, the Army extracted elements of existing units and formed them into what is known as derivative units. It has been staffing derivative units with individuals drawn from the original unit and other Selected Reserve units. According to its mobilization data, the Army formed over 700 derivative units for the Bosnia mission since December 1995. Examples of derivative units that have been mobilized for Bosnia include the target acquisition radar elements of National Guard divisions, elements of Army Reserve garrison support units, and platoons from postal companies. According to a FORSCOM operations official, extracting these elements often affects the ability of the parent unit to conduct its normal peacetime activities, such as training, much in the same way that it has affected split-based active units. In responding to a draft of this report, the Army stated that a positive effect of split-based operations is that the redeploying soldiers can bring better developed or newly acquired skills to the unit. The Army has also created derivative units, such as various mobilization support detachments, that are not elements of existing units. These detachments are ad hoc units created for the sole purpose of activating individuals with assorted capabilities that are needed to meet miscellaneous individual requirements. According to an Army Reserve Personnel Center official, this was done because PSRC authority did not allow for the call-up of individuals unless they were members of a unit in the Selected Reserve. The requirements have been met in part by members who initially belonged to the Individual Ready Reserve but volunteered to join the Selected Reserve temporarily so that they could be subject to PSRC. Of the previously mentioned 1,613 reservists provided by the Army Reserve Personnel Center and the U.S. Army Reserve Command, 1,068 were reservists from the Individual Ready Reserve who transferred to the Selected Reserve, including 551 who were placed into derivative units. The Army has conducted multiple force rotations for varying lengths of time to support the Bosnia mission. With the recent extension of the mission for an unspecified duration, the Army is planning to (1) replace forces currently deployed to Bosnia; (2) identify forces needed for future rotations; and (3) relieve pressure placed upon USAREUR, which has provided most of the forces for the Bosnia mission to date. Formal guidance has not been finalized regarding Bosnia mission needs after June 1998. In the meantime, USAREUR is making plans for a follow-on force. It intends to provide personnel for the initial follow-on force according to the current SFOR organization and authorized troop level of 8,500 troops in Bosnia. If the United States succeeds in its effort to have other troop-contributing nations provide more troops, the U.S. force level in Bosnia could drop to 6,900. A smaller force, according to USAREUR and FORSCOM officials, would most likely have fewer combat support and combat service support units. For example, one of the potential reductions involves having only one aviation brigade—a combat support unit—responsible for supporting the forces in Bosnia and the SFOR Commander’s reserve force. Additional force reductions will come from units such as the Army Center for Lessons Learned and military history units. With the decision to extend the Bosnia mission indefinitely, the Army canceled its June 1998 troop withdrawal and extended its plans for providing personnel beyond June. A USAREUR document on providing future forces specifies that the initial follow-on force deployment will be from June 1998 through October 1998. The Department of the Army has assigned USAREUR responsibility for providing the Army portion of this force. USAREUR has developed a strategy and identified those specific requirements that it can fill, which is most of the initial follow-on force requirements. According to USAREUR and FORSCOM officials, FORSCOM will provide most of the requirements that cannot be met by USAREUR units through October 1998. The Army plans for FORSCOM to provide most of the forces for the next two follow-on rotations—one in October 1998 and the other in April 1999. This decision was made to relieve USAREUR of the high operating and personnel tempo it has experienced since the Bosnia mission began and to allow it to focus on training for its wartime mission. According to USAREUR officials, FORSCOM’s providing the bulk of the forces for the Bosnia mission for a year will allow USAREUR to recover from the adverse impacts of almost 3 years continuous deployment to Bosnia.