	Introduction

Beginning with the early colonial settlements of America, the nation has provided benefits in varying degrees to those who have worn the uniform and suffered physical disabilities in service to the nation—sacrifices that are inherent to the profession of arms. Veterans could meet the burden of proving that their disabilities were service-connected through their military records, which may clearly describe and document the circumstances and medical treatment for an injury or an illness incurred while in service as well as any resulting disability. However, where the manifestation of the disabling disease or condition is remote from the veteran's service and any relation between the disability and service is not readily apparent, the burden of proving service connection can be a challenge. In such circumstances, Congress and the Department of Veterans Affairs (VA) have relied on presumptions to ease the burden placed on the veteran. It should also be noted that not all persons who served in the military are considered veterans for purposes of veterans benefits. Presumptive Service Connection

		What is a Presumption? In the context of VA claims adjudication, a presumption relieves veterans of the burden to prove that a disability or illness was caused by a specific exposure that occurred during service in the Armed Forces. When a disease is designated as presumptively service-connected, the individual veteran does not need to prove that the disease was incurred during service. Legislative History of Presumptions

The legislative history of veterans' disease presumptions dates back to 1921 when Congress, to ease the decision-making process in VA disability compensation adjudications, used its authority to establish service connection on a presumptive basis. 67-47) to the War Risk Insurance Act (P.L. 63-193). This amendment, among other things, established presumptions of service connection for active pulmonary tuberculosis and neuropsychiatric disease (later known as psychosis) occurring within two years of separation from active duty military service. 80-748), several additions were made to the list of presumptive diseases through regulation and executive order. The act required the VA to develop regulations for disability compensation for Vietnam veterans exposed to Agent Orange. 1990s-2000

In 1991, the Agent Orange Act ( P.L. 102-4 ) established for the first time a presumption of service connection for diseases associated with herbicide exposure (discussed in greater detail below). P.L. 102-4 authorized the VA to contract with the IOM to conduct a scientific review of the evidence linking certain medical conditions to herbicide exposure. 110-181 ), Congress established a presumption of service connection for purposes of VA medical care for any veteran of the Persian Gulf War who develops an active mental illness (other than psychosis) if such veteran develops such disability: (1) within two years after discharge or release from the active military, naval, or air service; and (2) before the end of the two-year period beginning on the last day of the Persian Gulf War. In addition to the scientific study mandated in P.L. Role of the Institute of Medicine (IOM)

As previously noted, the Agent Orange Act of 1991 established a new process for evaluating the health effects of exposure to herbicides containing dioxin and for establishing presumptions of service connection for diseases associated with such exposure.
The United States has provided benefits in varying degrees to those who have worn the uniform and suffered disabilities in service to the nation. In general, a veteran is entitled to compensation for disabilities incurred in or aggravated during active military, naval, or air service. It should be noted that not all persons who served in the military are considered veterans for purposes of veterans benefits. Veterans could meet the burden of proving that their disabilities are service-connected through their military records, which may clearly describe and document the circumstances and medical treatment for an injury or an illness incurred while in service as well as any resulting disability. However, where the manifestation of the disability is remote from the veteran's service and any relationship between the disability and service is not readily apparent, the burden of proving service connection can be a challenge. In such circumstances, Congress and the Department of Veterans Affairs (VA) have relied on presumptions. In the context of VA claims adjudication, a presumption could be seen as a procedure to relieve veterans of the burden to prove that a disability or illness was caused by a specific exposure that occurred during service in the Armed Forces. When a disease is designated as presumptively service-connected, the individual veteran does not need to prove that the disease was incurred during service.
The legislative history of veterans' disease presumptions dates back to 1921 when Congress established a presumption of service connection with an amendment (P.L. 67-47) to the War Risk Insurance Act (P.L. 63-193). It established presumptions of service connection for tuberculosis and neuropsychiatric disease (known today as psychosis) occurring within two years of separation from active duty military service. In the following years, additions to the presumptive list were made by regulation, executive order, and legislation. In the past 22 years, Congress has on three separate occasions created presumptive programs for three distinct groups of veterans: the so-called atomic veterans, who were exposed to radiation from above-ground nuclear tests and the atomic bombs detonated in Japan; Vietnam veterans; and Gulf War veterans. In addition, Congress has added certain disease conditions to the list of presumptions for specific groups of veterans such as former prisoners of war (POWs).
In 1991, the Agent Orange Act (P.L. 102-4) established for Vietnam veterans a presumption of a service connection for diseases associated with exposure to Agent Orange and other herbicides. For the first time, this act required the VA to contract with the Institute of Medicine (IOM) to conduct, every two years, a scientific review of the evidence linking certain medical conditions to herbicide exposure. The VA was instructed to use the IOM's findings, and other evidence, to issue regulations establishing a presumption for any disease for which there is scientific evidence of an association with herbicide exposure.
However, since an increasing proportion of service-connected disability compensation is paid through a presumptive decision-making process, some have raised several policy questions with regard to the current process. This report discusses presumptive service connection, its legislative history, and current challenges in making evidence-based determinations of presumptions. It also discusses the Agent Orange Act (P.L. 102-4) and suggests implications of the process established by the act for future presumptive service-connected determinations.