A conscientious objector is a person who is opposed in conscience to engaging in socially required behavior. Since the genuine objector will not be easily forced into acts he abhors and since compelling people to violate their own moral scruples is usually undesirable in a liberal society, those who formulate legal rules face the question whether conscientious objectors should be excused from legal requirements imposed on others. The issue is most striking in relation to compulsory military service: should those whose consciences forbid killing be conscripted for combat? Historically, conscientious objection has been considered mainly in that context, and the clash has been understood as between secular obligation and the sense of religious duty felt by members of pacifist sects. The Constitution says nothing directly about conscientious objection, and for most of the country's existence Congress was thought to have a free hand in deciding whether to afford any exemption and how to define the class of persons who would benefit. By now, it is evident that the religion clauses of the FIRST AMENDMENT impose significant constraints on how Congress may draw lines between those who receive an exemption from military service and those who do not. The Supreme Court has never accepted the argument that Congress is constitutionally required to establish an exemption from military service, but it has indicated that the Constitution does entitle some individuals to exemption from certain other sorts of compulsory laws.
The principle that society should excuse conscientious objectors from military service was widely recognized in the colonies and states prior to adoption of the Constitution. JAMES MADISON'S original proposal for the BILL OF RIGHTS included a clause that "no person religiously scrupulous of bearing arms shall be compelled to render military service in person," but that clause was dropped, partly because conscription was considered a state function. The 1864 Draft Act and the SELECTIVE SERVICE ACT of 1917 both contained exemptions limited to members of religious denominations whose creeds forbade participation in war. The 1917 act excused objectors only from combatant service, but the War Department permitted some of those also opposed to noncombatant military service to be released for civilian service.
The 1940 Selective Service Act set the basic terms of exemption from the system of compulsory military...