United States v. Seeger

A conscientious objector is someone who refuses to submit to conscription for military service on the basis of a moral prohibition against participation in war. It is customary for governments to require proof of commitment to a religious faith which proscribes military involvement. Examples of groups with deeply pacifist belief systems include Anabaptists, Mennonites, Amish, and Quakers. Thanks to effective lobbying in 1940, several of these groups secured the right of participation in Civilian Public Service (CPS) camps.

One may ask if it is unfair for such groups to enjoy the right of conscientious objection, since it would seem to violate the First Amendment separation of church and state. However, failure to respect their beliefs would violate these citizens' freedom of religion. Some pacifists have called for conscientious-objector provisions not related to religion, but again, it would be difficult to establish guidelines for such.