A conscientious objector is an "individual who has claimed the right to refuse to perform military service" on the grounds of freedom of thought, conscience, or religion. In general, conscientious objector status is considered only in the context of military conscription and is not applicable to volunteer military forces.
In some countries, conscientious objectors are assigned to an alternative civilian service as a substitute for conscription or military service. Some conscientious objectors consider themselves pacifist, non-interventionist, non-resistant, non-aggressionist, or antimilitarist.
On March 8, 1995 the United Nations Commission on Human Rights resolution 1995/83 stated that "persons performing military service should not be excluded from the right to have conscientious objections to military service." This was re-affirmed in 1998, when resolution 1998/77 recognized that "persons [already] performing military service may develop conscientious objections." A number of organizations around the world celebrate the principle on May 15 as International Conscientious Objectors Day. The term has also been extended to objecting to working for the military–industrial complex due to a crisis of conscience.
Historically, many conscientious objectors have been executed, imprisoned, or otherwise penalized when their beliefs led to actions conflicting with their society's legal system or government. The legal definition and status of conscientious objection has varied over the years and from nation to nation. Religious beliefs were a starting point in many nations for legally granting conscientious objector status.
An early recognition of conscientious objection was granted by William the Silent to the Dutch Mennonites in 1575. They could refuse military service in exchange for a monetary payment.
Formal legislation to exempt objectors from fighting was first granted in mid-18th century Great Britain following problems with attempting to force Quakers into military service. In 1757, when the first attempt was made to establish a British Militia as a professional national military reserve, a clause in the Militia Ballot Act allowed Quakers exemption from military service.