The term "Reserve Component" (RC) refers collectively to the seven individual reserve components of the Armed Forces: the Army National Guard of the United States, the Army Reserve, the Navy Reserve, the Marine Corps Reserve, the Air National Guard of the United States, the Air Force Reserve, and the Coast Guard Reserve. The purpose of these seven reserve components, as codified in law, is to "provide trained units and qualified persons available for active duty in the armed forces, in time of war or national emergency, and at such other times as the national security may require, to fill the needs of the armed forces whenever more units and persons are needed than are in the regular components." The Army National Guard and the Air National Guard also have a state role: operating under the control of their governor, they respond to various domestic emergencies, such as disasters and civil disorders. (For more information on the difference between the National Guard and other reserve components, see questions 5 and 11.) All individual reservists, whether members of the Reserve or the National Guard, are assigned to one of three major reserve categories: the Ready Reserve, the Standby Reserve, or the Retired Reserve. Reservists who are assigned to the Ready Reserve are further assigned to one of its three sub-components: the Selected Reserve, the Individual Ready Reserve (IRR), or the Inactive National Guard (ING). The differences between each of these categories are explained below. The Ready Reserve is the primary manpower pool of the reserve components. Members of the Ready Reserve will usually be called to active duty before members of the Standby Reserve or the Retired Reserve. The Ready Reserve comprises the Selected Reserve, the Individual Ready Reserve, and the Inactive National Guard, each of which is described below. The Selected Reserve contains those units and individuals within the Ready Reserve designated as so essential to initial wartime missions that they have priority over all other Reserves. Members of the Selected Reserve are generally required to perform one weekend of training each month ( inactive duty for training or IDT, also known colloquially as weekend drill ) and two weeks of training each year (annual training or AT) for which they receive pay and benefits. Some members of the Selected Reserve perform considerably more military duty than this, while others may only be required to perform the two weeks of annual training each year or other combinations of time. Members of the Selected Reserve can be involuntarily ordered to active duty under each of the main activation authorities (for example, Full Mobilization, Partial Mobilization, and Presidential Reserve Call-up; see question 9 for more information on activation authorities). The Individual Ready Reserve (IRR) is a manpower pool primarily composed of individuals who have already received military training, either in the Active Component or in the Selected Reserve. By law, members of the IRR may be required to perform regular training, but the Department of Defense does not currently require this. Members of the IRR can volunteer for training or active duty assignments, and they can also be involuntarily ordered to active duty under a Full Mobilization, Partial Mobilization, or a Disaster Response Activation. There is also a category of the IRR that can be activated during a Presidential Reserve Call-up, but at present there is no one assigned to this category. (See question 9 for more information on these activation authorities.) There is no IRR in the Army National Guard or the Air National Guard, although there is an analogous category in the Army National Guard known as the Inactive National Guard (see " The Inactive National Guard ," immediately below). The Inactive National Guard (ING) is, for practical purposes, the National Guard equivalent of the IRR. It comprises those members of the Army National Guard who are in an inactive status; currently there is no ING for the Air National Guard. They do not participate in training as do members of the Selected Reserve; however, they are attached to a specific National Guard unit and are required to meet with the unit once a year. Members of the ING can be involuntarily ordered to active duty if the unit they are attached to is activated under a Partial Mobilization, or a Full Mobilization. They are not subject to activation under a Presidential Reserve Call-up. (See question 9 for more information on these activation authorities.) The Standby Reserve comprises those individuals who have a temporary disability or hardship and those who hold key defense related positions in their civilian jobs. While in the Standby Reserve, reservists are not required to participate in military training and are subject to involuntary activation only in the case of a full mobilization. (See question 9 for more information on these activation authorities.) The Retired Reserve includes (1) Reserve officers and enlisted personnel who are receiving retired pay as a result of their reserve and/or active service; and (2) Reserve officers and enlisted personnel who transfer into the Retired Reserve after qualifying for reserve retirement, but before becoming eligible to receive retired pay (which normally occurs at age 60). Regular officers and enlisted personnel who are receiving retired pay are not included in the Retired Reserve. Members of the Retired Reserve may be involuntarily ordered to active duty in the event of a full mobilization, and some members of the Retired Reserve may be ordered to active duty in the event of a recall of retirees. (See " 9. How Are Reservists Called to Active Duty by the Federal Government? " for more information on activation authorities.) As of July 31, 2018, the total reported personnel strength of the Ready Reserve was 1,036,644. Table 1 breaks down this figure by service and category of reservist. In addition, there are about 13,000 members of the Standby Reserve and about 780,000 members of the Retired Reserve, although these categories of reservists are much less likely to be mobilized than Ready Reservists. Additionally, a substantial percentage of the Retired Reserve would likely be unable to mobilize due to age and fitness. Although the Reserves have been used extensively in support of operations since September 11, 2001, the overall authorized end-strength of the Selected Reserve declined by about 6% between 2001 and 2018 (874,664 for FY2001 versus 823,900 for FY2018). The largest reduction in authorized end-strength occurred in the Navy Reserve (-29,900 or -33.6%), while smaller reductions occurred in the Coast Guard Reserve (-1,000 or 12.5%), Air Force Reserve (-4,558 or -6.1%), Army Reserve (-5,800 or -2.8%), Marine Corps Reserve (-1,058 or -2.7%), Army National Guard (-7,026 or -2.0%), and Air National Guard (-1,422 or -1.3%). Reserve units are primarily filled by traditional reservists: members of the Selected Reserve who are usually required to work one weekend a month and two weeks a year. However, most reserve units are also staffed by one or more full-time civilian and/or military employees. These employees, known as full-time support (FTS) personnel, are "assigned to organize; administer; instruct; recruit and train; maintain supplies, equipment and aircraft; and perform other functions required on a daily basis in the execution of operational missions and readiness preparations" as authorized in Title 10, Title 5, and Title 32. There are five types of FTS personnel: Active Guard & Reserve, Military Technician, Non-Dual Status Technician, Active Component, and Civilian. The distinctions between each of these categories are outlined below. The mix of FTS personnel in each of the reserve components (RC) is intended "to optimize consistency and stability for each RC to achieve its assigned missions." Table 2 provides a summary of FTS personnel strength, broken down by service and category. Active Guard and Reserve (AGR) personnel are members of a Reserve Component who are placed on active duty or full-time National Guard duty orders for a period of 180 consecutive days or more for the purpose of "organizing, administering, recruiting, instructing, or training the reserve components." They may also perform certain operational support duties, and certain duties related to defense against weapons of mass destruction, as well as provide training to active component personnel, DOD contractors, DOD civilians, and foreign military personnel. Although they are serving full-time, AGR personnel are still considered members of the Selected Reserve. They are usually required to attend weekend drills and annual training with the reserve unit to which they are assigned. Depending on their branch of service, AGR personnel are referred to by different names. In the Army National Guard, Army Reserve, Air National Guard, and Air Force Reserve, they are simply referred to as AGRs, an acronym for Active Guard and Reserve. In the Navy Reserve they are referred to as TARs, an acronym for Training and Administration of Reserves. In the Marine Corps Reserve, they are known as Marine Corps Active Reserves or ARs. Military technicians (MTs) – referred to in statute as "military technicians (dual status)" -- are federal civilian employees who provide support to reserve units, either in the "organizing, administering, instructing or training of the Selected Reserve" or by maintaining and repairing reserve component equipment and supplies. Some MTs may also perform certain operational support duties and provide training to active component personnel, DOD contractors, DOD civilians, and foreign military personnel. Unlike regular civilian employees, MTs are generally required to maintain membership in the Selected Reserve as a condition of their employment. They are required to attend weekend drills and annual training with their reserve unit, which is usually the one that employs them as civilians during the week. Military technicians can be involuntarily ordered to active duty in the same way as other members of the Selected Reserve (see " 2. What Are the Different Categories of Reservists? "). There are no MTs in the Navy Reserve, the Marine Corps Reserve, or the Coast Guard Reserve. Non-dual status technicians (NDSTs) are civilian employees of the military departments serving in military technician positions. They are referred to as non-dual-status technicians because they are not members of the Selected Reserve and, hence, do not have a dual military/civilian status like MTs. NDSTs perform the same functions as MTs, but cannot be ordered to active duty as they do not have a military status. The number of NDSTs in the Army Reserve, Air Force Reserve, and National Guard is capped by law at 595, 90, and 1950 respectively. There are no NDSTs in the Navy Reserve, the Marine Corps Reserve, or the Coast Guard Reserve. Active Component (AC) personnel are active-duty members of the military who are "assigned or attached to [Reserve Component] organizations or units by their respective Service to provide advice, liaison, management, administration, training, and support." Although they are formally members of the Active Component, not the Reserve Component, AC personnel may deploy with the reserve unit to which they are assigned if the unit is mobilized. Civilians are federal civil service employees who "provide administration, training, maintenance, and recruiting support" to the Reserve Component. They are not required to hold membership in the Selected Reserve as a condition of their employment, although some do so voluntarily. Unless they are members of the reserve component, they cannot be involuntarily ordered to active duty. Although the term reserves is often used as a generic term to refer to all members of the seven individual reserve components, there is an important distinction between the five reserve components that are purely federal entities (i.e., the Army Reserve, Navy Reserve, Marine Corps Reserve, Air Force Reserve, and Coast Guard Reserve) and the two reserve components that are both federal and state entities (i.e., the Army National Guard and the Air National Guard). In this context, the five purely federal reserve components are referred to collectively as the Reserves, while the dual federal/state reserve components are referred to collectively as the National Guard. The Reserves are of comparatively recent origin, having all been established in the 20 th century. They were organized under Congress's constitutional authority "to raise and support Armies" and "to provide and maintain a Navy." The National Guard has a much longer historical pedigree. It is descended from the colonial-era militias that existed prior to the adoption of the Constitution. The Constitution does, however, contain provisions that recognize the existence of the militia and that give the federal government a certain amount of control over it. Unlike the Reserves, which are exclusively federal organizations, the National Guard is usually both a state and a federal organization. The National Guard of the United States is made up of 54 separate National Guard organizations: one for each state, and one for Puerto Rico, Guam, the U.S. Virgin Islands, and the District of Columbia. While the District of Columbia National Guard is an exclusively federal organization and operates under federal control at all times, the other 53 National Guards operate as state or territorial organizations most of the time. In this capacity, each of these 53 organizations is identified by its state or territorial name (e.g., the California National Guard or the Puerto Rico National Guard), and is controlled by its respective governor. Due to their dual federal and state role, National Guardsmen can be called to duty in several different ways (see questions 9 and 11) and the mode of activation has important implications for the pay, benefits, and legal protections they receive (see questions 10 and 12). In 2000, Charles Cragin, a former Assistant Secretary of Defense for Reserve Affairs, summed up the changing role of the reserve components in the following words: "The role of our Reserve forces is changing in the United States. We have seen their traditional role, which was to serve as manpower replacements in the event of some cataclysmic crisis, utterly transformed. They are no longer serving as the force of last resort, but as vital contributors on a day-to-day basis around the world." His comments, well supported by historical data at the time he made them, became even more apt given the large reserve mobilization that has occurred since the September 11 th terrorist attack on the United States. During the Cold War era, the reserve components were a manpower pool that was rarely tapped. From 1945 to 1989, reservists were involuntarily activated for federal service four times, an average of less than once per decade. These activations occurred only during wartime and national emergencies: the Korean War (1950-1953; 857,877 reservists involuntarily activated), the Berlin Crisis (1961-1962; 148,034 reservists involuntarily activated), the Cuban Missile Crisis (1962; 14,200 reservists involuntarily activated), and the Vietnam War/USS Pueblo Crisis (1968-1969; 37,643 reservists involuntarily activated). The nation has relied more heavily on the reserve components since the end of the Cold War. Reservists have been involuntarily activated for federal service six times over the past 28 years, with the activation initiated shortly after the 9/11 attacks continuing to the present and likely constituting the largest reserve activation since World War II. Some of these activations have been directly related to war or armed conflict: for example, the Persian Gulf War (1990-1991; 238,729 reservists involuntarily activated), the low-intensity conflict with Iraq (1998-2003; 6,108 reservists involuntarily activated), and military operations in the aftermath of the September 11 th terrorist attacks (2001-present; 959,701 reservists involuntarily and voluntarily activated as of September 4, 2018). Other activations have been in support of missions that were primarily peacekeeping and nation-building, such as the intervention in Haiti (1994-1996; 6,250 reservists involuntarily activated) and the Bosnian peacekeeping mission (1995-2004; 31,553 reservists involuntarily activated). The ongoing Kosovo mission (1999-present; 11,485 reservists involuntarily activated through 2003; no available data since then) has been a combination of armed conflict and peacekeeping. It is important to point out that—except for the activations in the aftermath of the September 11 th attacks—this tally of activations refers only to instances where reservists were involuntarily ordered into active federal service. It does not encompass the many instances where reservists have served on active duty under voluntary orders or annual training orders or, for members of the National Guard, service under state authority (see " 11. Are There Other Ways in Which Members of the National Guard Can Be Activated? " for more information on state active duty and duty under Title 32 of the U.S. Code). Data from the Office of the Assistant Secretary of Defense for Manpower and Reserve Affairs (OASD/M&RA) shed more light on the growing contribution of reservists to federal missions. According to OASD/RA, reservists contributed about 1 million duty-days per year to their respective services between fiscal years 1986 and 1989. This contribution increased since then to the point where reservists contributed about 13 million duty-days per year between fiscal years 1996 and 2001. With the large mobilization of reservists in the aftermath of the September 11 th attacks, reservists contributed about 41.3 million days in FY2002, rising to a peak of 68.3 million days in FY2005. This metric dropped to 17.3 million days by FY2014, but it still represents a vastly higher level of activity than typically occurred in the Cold War era. The continuing mobilization of reservists to participate in these operations lends support to the idea that the Reserve Component has been transformed from a "force of last resort" in the Cold War era into a more integrated part of the military services in the post-Cold War era. For more information on the history of reserve activations, see CRS Report RL30637, Involuntary Reserve Activations For U.S. Military Operations Since World War II , by [author name scrubbed]. The Posse Comitatus Act (18 U.S.C. 1385), along with other related laws and administrative provisions, prohibits the use of the military to execute civilian laws unless expressly authorized by the Constitution or an act of Congress. As a part of the military, the reserve components are generally covered under these provisions and thus are restricted in the same way that active component forces are. However, there are important exceptions to this general rule. First, Congress has made a number of exceptions to the Posse Comitatus Act that permit military involvement in law enforcement. For example, Congress has enacted several statutes that authorize the President to use military forces to suppress insurrections and domestic violence. If these statutes were to be invoked, the President could use the reserve component in the same way as active component forces to put down a rebellion or to control domestic violence. Another important exception relates to the Coast Guard, which Congress has vested with broad law enforcement authority. Under these statutory provisions, the Coast Guard Reserve can participate, like its active counterpart, in the enforcement of maritime, customs, and certain other federal laws. Second, when acting in its capacity as the organized militia of a state, the National Guard is not part of the federal military and thus is not covered by the Posse Comitatus Act. Only when it is called into federal service does the National Guard become subject to the act. As such, the National Guard can be used by state authorities to enforce the law. For example, while acting in a state capacity, the National Guard has been used for riot control and counter-drug activities. Additionally, it was used to provide increased security at airports throughout the country in the aftermath of the September 11 terrorist attacks and to assist with security and disaster relief missions in the aftermath of Hurricanes Katrina and Rita. For more information on the Posse Comitatus Act see CRS Report R42669, The Posse Comitatus Act and Related Matters: A Sketch , by [author name scrubbed]. This section focuses on the pay and benefits provided to participating members of the Selected Reserve when they are not serving on active duty. In general, when reservists are ordered to federal active duty for more than 30 days they receive pay and benefits virtually identical to those of active duty personnel, although there are some exceptions. When ordered to active duty for a period of 30 days or less, they receive most, but not all, of the pay and benefits that active duty personnel receive. Additionally, reservists who are not on active duty receive a different set of pay and benefits when they are serving in a reserve component category other than the Selected Reserve and members of the National Guard receive a different set of pay and benefits when they are serving full-time in a state status. Members of the Selected Reserve are generally required to work one weekend a month (called inactive duty for training or IDT; also known colloquially as drill ) and two weeks per year (called annual training or AT). They are paid for this work according to the same basic pay table used for their active duty counterparts. This table is based on both rank and years of service. Thus, reservists and active duty personnel of the same rank and the same longevity fall into the same category for basic pay. However, reservists and active duty personnel do not always accrue credit for a day of pay in the same manner. During AT, reservists receive one day of basic pay for each day of duty, just as active duty personnel receive one day of basic pay for each day of duty. Thus, for a typical AT of two weeks, a reservist receives 14 days of basic pay. However, during IDT reservists receive the equivalent of one day of basic pay for each unit training assembly (UTA) they attend. A UTA is generally a four-hour period of instruction, and there are usually four UTAs per drill weekend. Thus, for each two-day long drill weekend reservists receive the equivalent of four days of basic pay. During a typical year, then, a reservist who worked 38 days (14 days of annual training plus 24 days of IDT) would receive the equivalent of 62 days of basic pay (14 days of pay for annual training and 48 days of pay for IDT). Depending on the type of duty they are performing, reservists may also be eligible for special and incentive pays for performing certain types of hazardous or arduous duty, for serving in certain assignments, or for possessing certain skills. Reservists are generally eligible for special and incentive pays during AT under the same conditions as active component personnel. Typically, they may receive a pro-rated portion of the full monthly amount corresponding to the number of days served. Reservists may also be eligible for special and incentive pays during IDT, and typically receive such compensation at a rate proportional to the amount of inactive duty compensation they receive (i.e., one-thirtieth of the monthly rate for each unit training assembly). During AT, but not during IDT, reservists may be eligible for a housing allowance known as Basic Allowance for Housing-Reserve Component/Transit (BAH-RC/T), which is generally lower than the normal Basic Allowance for Housing (BAH), and for a subsistence allowance known as Basic Allowance for Subsistence (BAS). Reserve officers are also entitled to a $400 clothing allowance at the beginning of their reserve service to assist them in purchasing necessary uniform items. Furthermore, if they are called to active duty for more than 90 days, they are usually entitled to an additional $200 clothing allowance. Reserve enlisted personnel are typically issued all of their uniforms, shoes, boots, and insignia and therefore do not receive any clothing allowance; however, they may be eligible for a clothing allowance if required uniform items are not provided to them. Until 2004, non-activated reservists had only limited access to TRICARE, the military health care system. Specifically, they were entitled to treatment at a military medical facility for illnesses or injuries incurred or aggravated during IDT or AT, while traveling directly to or from their IDT or AT duty station, or while remaining overnight between successive periods of inactive duty training. Family members of reservists have generally not been eligible for military medical care during either IDT or AT, but became eligible if the reservist was ordered to active duty for more than 30 days. All of these provisions are still in effect today, but the 108 th and 109 th Congresses passed several provisions that provide premium-based access to TRICARE for non-activated reservists and their families. These provisions are discussed in more detail later in this report (see " 13. How Has Congress Changed Pay and Benefits for Reserve Component Personnel Since the September 11 th Attacks? "). Members of the Selected Reserve and Individual Ready Reserve are eligible to enroll in a dental plan known as the TRICARE Dental Program (TDP), provided they have at least 12 months of service remaining. The annual premium for the program is about $137 for a member of the Selected Reserve, and about $342 for members of the Individual Ready Reserve. In return, TDP provides up to $1,500 of coverage per year, per beneficiary, toward basic dental care procedures including diagnostic, endodontic, preventive, restorative services, and oral surgery. There is also a benefit for orthodontic services, which has a lifetime cap of $1,750 per beneficiary. Members of the Selected Reserve and Individual Ready Reserve may also enroll their families in the TDP, but doing so increases the annual premium by about $889 per year. Members of the Selected Reserve are eligible to purchase up to $400,000 of life insurance under the Servicemembers' Group Life Insurance (SGLI) program. The major benefits of this program are its relatively low cost and its guarantee of payment even if death occurs as a result of combat action (something private insurers do not always provide). Reservists who participate in SGLI can also purchase up to $100,000 of life insurance for their spouses and are provided with $10,000 of life insurance coverage per child at no cost. Members of the Selected Reserve and their family members have unlimited access to the commissary, a system of subsidized military grocery stores. Members of the Selected Reserve and their family members also have unlimited access to the military exchange system, a system of military department stores. Reservists become eligible for retirement after 20 years of qualifying service. A year of qualifying service is defined as a year in which a reservist has earned at least 50 retirement points . Reservists earn 15 retirement points per year simply for being a member of the Ready Reserve, one point for each unit training assembly (UTA), one point for each day of annual training (AT), and one point for each day of active duty. Points can also be earned for completing certain military correspondence or distance learning courses and for performing funeral honors duty. Earning 50 points in a given year is usually not difficult for members of the Selected Reserve; attending all weekend drills and two weeks of annual training generates 77 retirement points. Point totals are also important because they are used to calculate retired pay (see below). Excluding points earned while in an active duty status (which includes annual training), reservists may not earn more than 130 points per year. Additionally, including points earned while in an active duty status, reservists may not earn more than 365 points in a year (366 in a leap year). After completing 20 years of qualifying service, a reservist may apply for retirement. Upon retirement, but before reaching the retired pay eligibility age , a reservist is entitled to a limited number of benefits, including unlimited use of the military exchange, commissary system, and other military facilities, and space available travel on military aircraft within the United States and its territories. Upon reaching the retired pay eligibility age—which can range between 50 and 60 depending on how many days of certain types of duty the reservist performed during his career —the retired reservist is eligible to receive retired pay. At age 60, the retired reservist is entitled to benefits identical to those of active duty retirees, including space-available travel on military aircraft throughout the world and access to military health care benefits. Retired pay is calculated by totaling all the points earned during all the years of service, then dividing this sum by 360. This calculation produces the number of equivalent years of active duty service the reservist has performed. The number of equivalent years is then multiplied by 2.5% or 2.0% (depending on the date of entry to military service) to determine the retirement benefit multiplier . This multiplier is then applied to an amount based on the monthly base pay earned by an active duty servicemember with similar rank and years of service. For example, a reservist who accrues 2,500 points over the course of 20 qualifying years would be deemed to have completed the equivalent of 6.94 years of active service (2,500 divided by 360). This figure, when multiplied by 2.5%, produces a multiplier of 17.3%. Assuming that the basic pay for an active duty servicemember with similar rank and longevity was $3,000 per month, the reservist would be entitled to retired pay in the amount of $519 per month (17.3% of $3,000). At present, there are four major statutory provisions by which reservists can be involuntarily ordered to active duty by the federal government for an extended period of time, another provision specifically for involuntarily activating members of the federal reserve components for short periods of time to respond to disasters or emergencies, and a provision for the recall of retired reservists. (For a discussion of additional ways in which members of the National Guard can be called up in a nonfederal status, see question 11.) These provisions differ from each other in terms of the statutory requirements for utilization, the number and category of reservists called up, and the duration of the call-up. Three of the five authorities are decades old and are commonly referred to as Full Mobilization, Partial Mobilization, and Presidential Reserve Call-up (PRC). The other two authorities, added in 2011, do not yet have common names, but are referred to in this report as Combatant Command Support Activation and Disaster Response Activation. Each of these authorities is detailed below. In time of war or national emergency declared by Congress, or when otherwise authorized by law, Section 12301(a) of Title 10 U.S.C. permits the Service Secretaries to authorize the involuntary activation of any member of the reserve components under his or her jurisdiction. There is no limit on the number of reservists ordered to active duty under this provision and mobilized reservists may be kept on active duty for the duration of the war or emergency plus six months. In time of a national emergency declared by the President, or when otherwise authorized by law, Section 12302 of Title 10 U.S.C. permits the Service Secretaries to authorize the involuntary activation of members of the Ready Reserve under his or her jurisdiction for a period not to exceed 24 consecutive months. Up to 1 million members of the Ready Reserve may serve on active duty at any one time under this provision of law. Reservists may be mobilized under this provision of law without approval from Congress. President George H.W. Bush invoked this authority to mobilize reservists during the latter part of the Persian Gulf War (1991) when the PRC authority was no longer sufficient to activate the number of reservists needed. President George W. Bush invoked this authority in the aftermath of the September 11 th terrorist attacks. It has been used to mobilize reservists for Operations Noble Eagle, Enduring Freedom, Iraqi Freedom, New Dawn, Freedom's Sentinel, and Inherent Resolve. Activations under this authority have continued to the present. Section 12304 of Title 10 U.S.C. permits the President to authorize the involuntary activation of members of the Selected Reserve and the Individual Ready Reserve for a period up to 365 consecutive days. Under this authority, up to 200,000 members of the Selected Reserve and the Individual Ready Reserve mobilization category —a sub-component of the Individual Ready Reserve that is currently not being used —may serve on active duty at one time. The President may activate reservists under this provision of law without approval from Congress; however, he is required to notify Congress within 24 hours of such an action. This authority was used to mobilize reservists during the early part of the Persian Gulf War (1990-1991), during the intervention in Haiti (1994-1996), during the Bosnian peacekeeping mission (1995-2004), during the low-intensity conflict with Iraq (1998-2003), and during the early years of the Kosovo conflict and peacekeeping mission (1999-present). Those activated under this authority may not be used to enforce federal authority or to suppress insurrection; nor may they be used to provide assistance to the federal government or the states for disaster response, unless responding to an emergency involving the use or threatened use of weapons of mass destruction or an actual or threatened terrorist attack of significant proportions. The National Defense Authorization Act for Fiscal Year 2012 contained a provision, codified at 10 U.S.C. 12304b, to allow involuntary activations of Selected Reserve units for up to 365 consecutive days of active duty in support of a combatant command. No more than 60,000 members of the National Guard and Reserves may be serving on active duty under this authority at any given time. The authority to activate reservists under this provision rests with the Service Secretary, but it may only be invoked for a "preplanned mission in support of a combatant command" where the costs of the activations and a description of the mission are included in the service's budget materials. According to the committee report that accompanied the Senate version of the bill, this new authority "is not designed for use for emergent operational or humanitarian missions, but rather to enhance the use of reserve component units that organize, train, and plan to support operational mission requirements to the same standards as active component units under service force generation plans in a cyclic, periodic, and predictable manner." This provision is codified at 10 U.S.C. 12304b. The Services currently use this authority for a number of missions, including Kosovo, Multinational Force and Observers (Sinai), and air defense of the national capital region. A separate provision in the National Defense Authorization Act for Fiscal Year 2012, now codified at 10 U.S.C. 12304a, allows the Secretary of Defense to involuntarily order units and individuals of the Army Reserve, Navy Reserve, Marine Corps Reserve, and Air Force Reserve to active duty for up to 120 days "when a governor requests federal assistance in responding to a major disaster or emergency." National Guard forces are not included in this authority; state and territorial governors already have the ability to activate their National Guard forces and to request support from other state and territorial National Guards under the Emergency Management Assistance Compact. The Coast Guard Reserve already has a short-term, disaster response activation authority in 14 U.S.C. 712. This provision also contained language specifying that when the federal armed forces and the National Guard are employed simultaneously in support of civil authorities within the United States, a dual status commander should be appointed. A dual status commander is a military officer who simultaneously serves as a state National Guard officer under the control of his or her governor, and as a federal military officer under the control of the President. A dual status commander is thus able to command nonfederalized National Guard forces and federal forces via these separate chains of command. The language of this provision also specifies that "when a major disaster or emergency occurs in any area subject to the laws of any State, Territory, or the District of Columbia, the Governor of the State affected normally should be the principal authority supported by the primary Federal agency and its supporting Federal entities, and the Adjutant General of the State or his or her subordinate designee normally should be the principal military authority supported by the dual-status commander when acting in his or her State capacity." Members of the Retired Reserve can be involuntarily ordered to active duty in the case of a Full Mobilization (see " Full Mobilization ," above). Under this authority, there is no limit on the number of retired reservists who can be called to active duty, and they may be kept on active duty for the duration of the war or emergency plus six months. Additionally, the Secretary of each military department has the authority to involuntarily order certain members of the Retired Reserve to active duty at any time, but this authority only applies to members of the Retired Reserve who have a regular retirement (at least 20 years of active duty). There is a limit on the amount of time recalled retirees can serve, and a limit on the number of officers recalled, but these limits do not apply in times of war or national emergency declared by Congress or the President. All reservists serving in Operations Enduring Freedom, Freedom's Sentinel, and Inherent Resolve are serving in a federal status in support of a contingency operation. As such, they are entitled to pay, benefits, and legal protections that are virtually identical to those provided to active duty servicemembers. Specifically, they are entitled to basic pay at the same rate as active duty and, if qualified, may receive special and incentive pays including Hazardous Duty Pay, Aviation Career Incentive Pay, Hostile Fire/Imminent Danger Pay, and special pays for health professionals. They are also entitled to a variety of allowances that are not taxable, including Basic Allowance for Housing (BAH), Basic Allowance for Subsistence (BAS), and, if separated from their families, a Family Separation Allowance (FSA). Medical and dental coverage for these reservists and their family members is virtually identical to that provided to active duty servicemembers, provided the orders are for more than 30 days. Leave is accrued in the same manner as for active duty personnel. They may use legal assistance, child care centers, space available travel, and morale, welfare, and recreation (MWR) services. Finally, they are protected by both the Uniformed Services Employment and Reemployment Rights Act (USERRA), the Servicemembers' Civil Relief Act (SCRA), and the Military Lending Act (MLA). The status of reservists supporting Operation Noble Eagle has been more varied. Some have been called up in a strictly federal status and, therefore, received pay, benefits, and legal protections identical to those of reservists serving in support of Operation Enduring Freedom. Certain members of the National Guard have been called up in a purely state status, or under state control but with federal pay and benefits. They received a different set of pay, benefits, and protections. For more information on these distinctions, see " 11. Are There Other Ways in Which Members of the National Guard Can Be Activated? " and " 12. What Type of Legal Protections Do Reservists Have When They Are Serving on Active Duty? What Reemployment Rights Do Reservists Have after Being Released from Active Duty? " Yes. Because the National Guard is, uniquely, both a state and federal organization (see question 5), its members can be called to active duty either in an exclusively federal status, in an exclusively state status, or under state control with federal pay and benefits. As members of the Reserve Component, National Guardsmen can be called to federal active duty in the same way as other reservists (see question 9). When this happens, control passes from the governor of the affected units and personnel to the President of the United States. When in federal service, Guard units and personnel typically perform military training or participate in military operations and they are entitled to the same pay, benefits, and legal protections as other reservists in federal service. As members of the militia of their state or territory, National Guard personnel may also be called up by their governor for full-time duty. When employed in this capacity, referred to as state active duty, National Guardsmen are state or territorial employees, not federal employees, and their pay and benefits are determined by state or territorial law. They are not eligible for protection under the Servicemembers' Civil Relief Act or the Uniformed Services Employment and Reemployment Rights Act (see question 12), although they may be protected by analogous laws enacted at the state level. Typical missions performed under state active duty include responding to disasters and civil disorders. Additionally, shortly after September 11, 2001, some governors called up members of the National Guard to protect critical infrastructure in their states, such as nuclear power plants, water treatment facilities, and bridges, from potential terrorist attacks. A third form of duty for National Guard personnel involves duty under state control but with pay and benefits provided by the federal government. This is sometimes referred to as Title 32 status in reference to the part of the U.S. Code that governs this duty status. Typical duties performed in this status include inactive duty for training (IDT or weekend drill ) and annual training (AT) within the United States. Another type of duty that falls into this category is specified in Title 32 of the U.S. Code, Section 502(f). This provision of law provides that "a member of the National Guard may ... without his consent, but with the pay and allowances provided by law ... be ordered to perform training or other duty in addition to that prescribed under subsection (a) [i.e., IDT or AT]." This is the provision of law used to provide federal pay and benefits to the Guardsmen called up to provide security at many of the nation's airports in the aftermath of the terrorist attacks of September 11, 2001, to assist with the response to Hurricanes Katrina and Rita in 2005, and to support the southwest border security mission in 2006-2008, 2010-2016, and 2018-present. Guardsmen called up under this authority receive federal pay and benefits, and are entitled to certain legal protections as though they were in federal service, but they otherwise operate in a manner similar to state duty. When they are called into active federal service, reservists become eligible for a broad array of legal protections including the Servicemembers Civil Relief Act (SCRA), the Uniformed Services Employment and Reemployment Rights Act (USERRA) of 1994, and the Military Lending Act (MLA). The SCRA amended and renamed the Soldiers' and Sailors' Civil Relief Act (SSCRA) of 1940. Among other things, the SCRA provides most people called to active duty with certain protections against rental property evictions, mortgage foreclosures, insurance cancellations, and government property seizures to pay tax bills. It also limits to 6% the interest rate that the activated servicemember has to pay on loans incurred prior to activation. (Note, however, that National Guardsmen who are serving in a state status are not covered by the SCRA. National Guardsmen performing full-time National Guard duty under Title 32 of the U.S. Code are covered by the SCRA in certain circumstances.) For a more complete description of the legal protections provided to activated reservists by the SCRA, see CRS Report R45283, The Servicemembers Civil Relief Act (SCRA): Section-by-Section Summary , by [author name scrubbed]. Reservists' employment and reemployment rights are covered under USERRA. USERRA prohibits employers from discriminating against reservists—including National Guard personnel performing full-time National Guard duty under Title 32 of the U.S. Code, but not those performing state active duty (see " 11. Are There Other Ways in Which Members of the National Guard Can Be Activated? ")—with respect to hiring, retention, promotion, or other benefits and it requires employers to give these individuals time off for military service, regardless of whether the service is voluntary or involuntary. This time off is treated as a furlough or leave of absence and the reservist may not be required to use vacation leave, annual leave, or similar leave. Upon completion of such military service, USERRA generally gives the reservist a right to reemployment. Although there are some exceptions, a reservist is usually entitled to be promptly reemployed by his or her civilian employer and, depending on certain factors, to be reinstated to either (1) the job that the reservist would have held if the reservist's employment had not been interrupted by military service, (2) the job that the reservist actually held at the time military service began, or (3) a job comparable to the one the reservist held at the time military service began. A comparable job is one of similar pay, status, and seniority that the reservist is qualified to perform. Finally, upon reinstatement, the reservist is entitled not only to the seniority and seniority-based benefits he or she held at the time military service began but also to any additional seniority and seniority-based benefits that the reservist would have earned if he or she had remained continuously employed. For example, consider a reservist who has nine years of seniority with his or her civilian employer and leaves to perform two years of military service. Upon returning to work at the end of that two-year period, the reservist will be considered to have 11 years of seniority with the civilian employer and all concomitant rights and benefits. USERRA also provides protection to reservists with respect to job retraining, employer-provided health care plans, and employer provided pension plans. Reservists are obligated to notify their employers as soon as possible about upcoming military service. They also have an obligation to report to work, or to notify their employers that they intend to report to work, within a relatively short time after being released from active duty. Failure to meet these obligations may effectively nullify a reservist's right to reemployment. Reservists who believe their civilian employer has violated their rights under USERRA have several options. The first is to contact their commanding officer, who may be able to resolve the issue with the employer. Alternatively, reservists may contact the National Committee for Employer Support of the Guard and Reserve (NCESGR), a Department of Defense organization that will contact the employer and attempt to resolve the problem informally. A complaint can also be made to the Veterans' Employment and Training Service (VETS) of the Department of Labor. VETS has the power to investigate complaints and attempt to resolve them through negotiation or mediation. If that fails, the servicemember may request that VETS refer the case to the Department of Justice (for those who are not federal employees) or to the Office of Special Counsel (for federal employees). "If the Attorney General is reasonably satisfied that the service member is entitled to relief, the Attorney General may exercise DOJ's prosecutorial authority and commence an action in Federal court on behalf of the service member." The Office of Special Counsel reviews cases of federal employees in a similar manner and may represent the servicemember before the Merit Systems Protection Board (MSPB). Additionally, servicemembers have the option of hiring a private attorney to pursue a claim in court or before the MSPB. The MLA was enacted with the National Defense Authorization Act for Fiscal Year 2007 and amended by the National Defense Authorization Act for Fiscal Year 2013. The impetus for the law was perception of a need to protect servicemembers from certain "predatory" lending practices as identified in a congressionally mandated DOD study. The MLA prescribes limitations on terms for consumer credit extended to covered servicemembers and dependents, including a Military Annual Percentage Rate (MAPR) limit of 36% on certain credit products. Creditors must provide specific disclosures about loan rates and certain lending practices are banned. Congress has made many changes in Reserve Component pay and benefits since the September 11 th attacks. Selected changes discussed below are (1) establishing a premium-based TRICARE benefit for non-activated reservists, (2) creating new educational benefits for reservists who have been mobilized since September 11, 2001, (3) providing additional compensation for certain reservists who experience a reduction in income when activated, and (4) reducing below 60 the age at which certain reservists can draw retired pay. Each of these changes is discussed below. When ordered to federal active duty for more than 30 days, members of the National Guard and Reserves are entitled to receive medical benefits under TRICARE (the military's health care system) for themselves and their family members. Prior to 2004, non-activated reservists had limited access to TRICARE for themselves and no access for their families. This began to change in the 108 th and 109 th Congresses, both of which passed provisions expanding access to TRICARE for non-activated reservists and their families. In 2004, Congress authorized the TRICARE Reserve Select (TRS) program for Reserve Component members. After several modifications the current program permits most members of the Selected Reserve who are not on active duty to obtain coverage similar to that of TRICARE Standard and TRICARE Extra by paying a premium of 28% of the total cost of their coverage. The premiums for TRS coverage through December 2018 are $46.09 per month for an individual reservist and $221.38 per month for the reservist and his family members. Both the 108 th and 110 th Congresses passed legislation that provides enhanced GI Bill-type educational benefits for reservists who have served in support of a contingency operation since September 11, 2001. Prior to passage of these laws, there were two main educational assistance programs for military personnel: the Montgomery G.I. Bill-Active Duty (MGIB-AD) and the Montgomery G.I. Bill-Selected Reserve (MGIB-SR). Eligibility for the basic MGIB-AD benefit typically requires three years of continuous active duty service and a deduction totaling $1,200 from the servicemember's pay. As of October 1, 2018 MGIB-AD provides a basic benefit for full-time study of $1,994 per month, for up to 36 months. Eligibility for the MGIB-SR benefit requires a six-year commitment to serve in the Selected Reserve, but requires no contributions on the part of the reservist. As of October 1, 2018 MGIB-SR provides a basic benefit for full-time study provided of $384 per month, for up to 36 months. Although the MGIB-SR program requires no contribution (as the MGIB-AD program does), the monthly benefit under MGIB-SR is about 20% of the amount of the MGIB-AD benefit. While reservists who served on active duty for at least 24 consecutive months were eligible for a reduced MGIB-AD benefit (provided they contributed $1,200 like their active duty peers), those reservists who served less than 24 consecutive months generally remained eligible only for the MGIB-SR until 2004, when Congress established the Reserve Educational Assistance Program. In 2004, Congress established the Reserve Educational Assistance Program (REAP) to provide enhanced educational benefits to reservists who were called or ordered to active service in response to a war or national emergency declared by the President or Congress. However, several years later Congress approved the Post‐9/11 Veterans Educational Assistance Act, which provides more generous educational benefits than REAP. The FY2016 National Defense Authorization Act limited REAP to those who were receiving REAP benefits at that time "for a course of study at an educational institution for the enrollment period at the educational institution that immediately preceded the date of the enactment of that Act." It also added a sunset clause to REAP, terminating it in 2019. Under REAP, eligible reservists receive the following educational benefit for full-time study for up to 36 months: 40% of the MGIB-AD basic benefit for those serving at least 90 consecutive days but less than one consecutive year; 60% of the MGIB-AD basic benefit for those serving at least one consecutive year but less than two consecutive years; and 80% of the MGIB-AD basic benefit for those serving at least two consecutive years or three aggregate years. As of October 1, 2018, the 40% benefit equates to $797.60 per month, the 60% benefit equates to $1,196.40 per month, and the 80% benefit equates to $1,595.20 per month. REAP did not require any contribution on the part of reservists like the MGIB-AD program does. The Post-9/11 Veterans Educational Assistance Act of 2008, also known as the Post-9/11 GI Bill, took effect on August 1, 2009. The formula used for calculating benefits under this program is differs from the set rate used by the MGIB-AD, MGIB-SR and REAP programs. Instead, the maximum benefit is linked to each individual's "subsistence, tuition, fees, and other educational costs" while participating in an approved program of education. In general, reservists who have been activated since September 11, 2001, will receive a significantly greater benefit under the Post-9/11 GI Bill than under MGIB-SR, MGIB-AD, or REAP. The maximum benefit under this law is provided to (1) individuals who have served at least 36 aggregate months on active duty in the armed forces after September 10, 2001 and who subsequently continue to serve or who are discharged or released from service under specified conditions; (2) individuals who have served at least 30 continuous days of active duty after September 10, 2001 and who are discharged or released from active duty for a service-connected disability; and (3) individuals awarded the Purple Heart for service occurring after September 10, 2001. For reserve component personnel, the law defines "active duty" as service under nine specific activation authorities of Title 10, two additional types of service by National Guard personnel under Title 32, and one additional type of service by Coast Guard reservists. A reduced benefit is available to individuals who have served at least 90 aggregate days, but less than 36 aggregate months. This reduced benefit is scaled so that those serving longer aggregate periods of time on active duty receive a higher benefit than those serving shorter aggregate periods of time. The amount of the educational assistance benefit has three major components. The first provides a payment to cover "the actual net cost for in-State tuition and fees" for public institutions of higher learning, and up to $23,671.94 per year for private or foreign institutions as of August 1, 2018. This amount is reduced by waivers or reductions of tuition and fees, and by certain types of scholarships and student aid. The second major component provides a monthly housing stipend equal to the Basic Allowance for Housing that an active duty servicemember in paygrade E-5, with dependents, would receive if living in the area where the institution of higher learning is located. The third component provides a payment of $1,000 per academic year to cover "books, supplies, equipment and other educational costs." In addition to the educational assistance benefit, the Post-9/11 GI Bill may also provide a tutorial assistance benefit of up to $100 per month (not to exceed $1,200 total), a one-time relocation and travel assistance payment of $500, a payment of up to $2,000 for each licensure and certification test, and a payment to cover the cost of a national test to gain admission to, or course credit at, an institution of higher learning. Other provisions of the bill allow for enhanced benefits for servicemembers with critical skills or who perform additional service, and for servicemembers attending schools which have entered into a matching contribution program known as the Yellow Ribbon G.I. Education Enhancement Program . The bill allows eligible servicemembers to transfer some or all of their benefits to a spouse and children. Beginning in FY2019, the VA is authorized to grant up to an additional nine months of limited entitlement to selected Post-9/11 GI Bill participants under the Edith Nourse Rogers STEM Scholarship. The mobilization of reservists in the aftermath of the September 11, 2001, terrorist attacks likely has been the largest since the Korean War and is one of the longest ongoing mobilizations ever. Some reservists have experienced financial losses when moving from their civilian jobs to full-time military status. These losses occur due to differences between the reservists' military and civilian pay, expenses incurred by reservists because of mobilization, and the decline in business experienced by self-employed reservists during and after release from active duty. This has generated numerous complaints from mobilized reservists and helped generate congressional interest in the subject. The 109 th Congress enacted a provision that provides a special payment of up to $3,000 to certain reservists who experience income loss while involuntarily mobilized. Reservists who have experienced income loss become eligible for these payments in every full month of active duty following the month in which they (1) complete 547 consecutive days (18 consecutive months) of active duty under an involuntary mobilization order; (2) complete 730 days of active duty under an involuntary mobilization order out of the previous 1,826 days (24 out of 60 months); or (3) are involuntarily mobilized for a period of 180 days or more within 180 days of a previous period of involuntary active duty for a period of 180 days or more. The amount of compensation available under this provision is equal to the reservist's average monthly civilian income minus total monthly military compensation . However, payments shall be made only if the differential is at least $50 per month and may not exceed $3,000 per month. Involuntary orders to full-time National Guard duty under 32 U.S.C. 502(f)(1) count as qualifying duty for the purposes of this payment. The 111 th Congress enacted a provision, codified at 5 U.S.C. 5538, to minimize the income loss of civilian employees of the federal government who are involuntarily ordered to active duty or involuntarily retained on active duty. It does so by providing differential pay —a payment equal to the amount by which a reservist's military pay and allowances are lower than his or her civilian basic pay. Specific eligibility criteria and the method for calculating the amount of differential pay are outlined in a memorandum issued by the Office of Personnel Management. This provision only applies to federal government employees, but it is not limited to cases of extended or frequent activations like the Income Replacement provision discussed in the previous paragraph; entitlement begins immediately following involuntary activation. Full-time National Guard duty under Title 32 does not count as qualifying duty for the purposes of this payment. After completing 20 years of qualifying service, a reservist may apply for retirement. Once retired, the reservist is entitled to receive certain benefits immediately; however, until recently he or she was not entitled to receive retired pay until the age of 60. In light of the heavy use of the Reserve Component in recent years, a number of legislative proposals were introduced in the 108 th and 109 th Congresses to lower the age at which reservists receive retired pay and military retiree health care benefits. During the 110 th Congress, a provision was included in the National Defense Authorization Act for FY2008 that permits certain reservists to draw retired pay as early as age 50, while maintaining the age for access to the military health care system at 60. This provision reduced the age for receipt of retired pay for members of the Ready Reserve by three months for each aggregate of 90 days of specified duty performed in any fiscal year after January 28, 2008 (the date of enactment of the FY2008 National Defense Authorization Act). Specified duty includes active duty under any provision of law to which 10 U.S.C. §101(a)(13)(B) refers, active duty under 10 U.S.C. §12301(d), or active service under 32 U.S.C. §502(f) if responding to a national emergency declared by the President or supported by federal funds. The retired pay eligibility age cannot be reduced below age 50; eligibility for retiree health care benefits remains at age 60. This law has no effect on reservists who were already retired as of January 28, 2008; reservists who do not perform any of the types of specified duty during their careers; or reservists who only performed the specified duty prior to January 28, 2008. It only reduces the retirement age for those reservists who perform qualifying duty after January 28, 2008.

Summary: The Constitution provides Congress with broad powers over the Armed Forces, including the power to "to raise and support Armies," "to provide and maintain a Navy," "to make Rules for the Government and Regulation of the land and naval Forces" and "to provide for organizing, arming, and disciplining the Militia, and for governing such Part of them as may be employed in the Service of the United States.... " In the exercise of this constitutional authority, Congress has historically shown great interest in various issues that bear on the vitality of the reserve components, such as funding, equipment, and personnel policy. This report is designed to provide an overview of key reserve component personnel issues. The term "Reserve Component" refers collectively to the seven individual reserve components of the Armed Forces: the Army National Guard of the United States, the Army Reserve, the Navy Reserve, the Marine Corps Reserve, the Air National Guard of the United States, the Air Force Reserve, and the Coast Guard Reserve. The purpose of these seven reserve components, as codified in law at 10 U.S.C. §10102, is to "provide trained units and qualified persons available for active duty in the armed forces, in time of war or national emergency, and at such other times as the national security may require, to fill the needs of the armed forces whenever more units and persons are needed than are in the regular components." During the Cold War era, the reserve components were a manpower pool that was rarely tapped. From 1945 to 1989, reservists were involuntarily activated by the federal government four times, an average of less than once per decade. Since the end of the Cold War, the nation has relied more heavily on the reserve components. Reservists have been involuntarily activated for contingency operations by the federal government six times since 1990, an average of about once every five years, including large-scale mobilizations for the Persian Gulf War (1990-1991) and in the aftermath of the September 11 terrorist attacks (2001-present). Additionally, starting in FY2014, the Services began involuntarily activating reservists under a new authority for pre-planned missions in support of Combatant Commanders. This report provides insight to reserve component personnel issues through a series of questions and answers that address How reserve component personnel are organized (questions 2 and 4); How many people are in each of the different categories of the reserve component (question 3); How reserve component personnel have been and may be used (questions 1, 5, 6, 7, 9, and 11); How reserve component personnel are compensated (questions 8 and 10); The types of legal protections that exist for reserve component personnel (question 12); and Recent changes in reserve component pay and benefits made by Congress (question 13).