Let's take a look at what happened to persons who declared themselves as conscientious objectors throughout American history. Apologies in advance to noders from around the world whose countries probably have their own stories to tell on this subject.
Prior to the American Revolution most conscientious objectors belonged to what were called "peace" churches. The most famous examples would be the Quakers and Mennonites - both of whom opposed war as a matter of their Christian principles. These groups were also among the first European colonists of North America. Their beliefs were tested when conflicts arose between the white settlers and Native Americans. The members of the peace churches who refused to take up arms or build fortifications wound up being persecuted by the Puritans, who considered the wars against Native Americans as the "Lord's Revenge."
During the 1600s some of the more enlightened colonies had exempted the Quakers and other members of peace churches from military service. Other colonies, however, were less tolerant. They fined or imprisoned citizens who refused to serve in militias or maintain forts. During the French and Indian War, some colonial governments forced them to pay for substitutes or face the prospect of their property being confiscated.
During the American Revolution, the anti-British forces expected those people who were conscientious objectors to help provision troops. Any who refused had their property raided and some were forced into service.
During the War of 1812, the political leaders of the day actually considered a national conscription to supplement the state militias. Daniel Webster took up the cause and argued successfully before Congress that such a measure would be unconstitutional. This left the matter of conscription up to the states. Members of the peace churches continued to resist military service and refused to pay any fines that were imposed as well as refusing to pay war related taxes. Many of these
folks had their property confiscated by local authorities.
In the 1830's, conscientious objection took on a political as well as religious implications. Movements such as the American Peace Society combined Christian ethics, the abolition of slavery and pacifism to new heights. In 1846, they led an organized campaign against the Mexican War. In a classic example of non-violence used to bring about social change, Henry David Thoreau refused to pay war taxes and was subsequently imprisoned.
During the American Civil War the first federal conscription legislation was passed. It required all male citizens between the ages of twenty and forty five to serve in the military if called. There were no exemptions for those who considered themselves conscientious objectors but one could buy their way out with a payment of three hundred dollars. Draft riots broke out among poorer citizens for two reasons. One because they could not afford to pay and two, because of the class bias that was implicit in the legislation.
During World War I only members of recognized peace churches were granted noncombatant status as an alternative to military service. Anybody who belonged to a religion that did not have a traditional antiwar stance, or who opposed war for political reasons, or who simply refused compulsory service were either forcibly inducted, court martialed, and sentenced to terms in military camps or prisons. About 500 objectors wound up being court martialed. Of those, 17 were sentenced to death and 142 received life sentences. While none of the death sentences were carried out and many of the sentences were reduced, the message was clear. Guards at the camps subjected to objectors to physical abuse, compulsory exercise, cold showers, solitary confinement, and reduced rations.
The majority of World War I objectors were Quakers, Mennonites, Seventh Day Adventists and Jehovah's Witnesses. Smaller numbers of objectors included socialists and anarchists. Some of the more famous people of the time that supported the objectors were Jane Addams, Emma Goldman and Eugene Debs. Each one of them supported the First Amendment rights that allows Americans to voice opposition to war. The American government and the majority of the citizenry took a different view. Goldman, along with thousands of other "subversives" was deported without trial and Debs was sentenced to ten years in prison for giving an anti-war speech.
During World War II, the Selective Training and Service Act exempted from military service those people who "by reason of religious training and belief" opposed war. It mandated that those seeking that status had to perform alternative service in work of "national importance". This included work on conservation projects, staffing of mental hospitals, and "volunteering" as human guinea pigs in government sponsored experiments. These experiments included diet endurance (starvation), transmission of malaria, hookworm, typhus and infectious hepatitis. They received no pay or benefits.
Those who refused any of the alternatives or failed the test for religious conviction were sentenced to prison. Most of those were Jehovah's Witnesses but some were affiliated with the War Resisters League, the Catholic Workers movement, or the Socialist Party.
It's estimated that about four hundred African-Americans refused to serve in WWII. Some of these objectors belonged to the Nation of Islam which viewed the war as a "white man's conflict". Other refused to serve in an army or fight for a country that denied basic freedoms to the black citizenry.
During the Vietnam War, Selective Service denied exemption to conscientious objectors whose views were "essentially political, sociological or philosophical." Given the unpopularity of the Vietnam War, the number of political objectors far outnumbered those who objected on religious convictions. These political objectors also benefited from a larger degree of public support. Many coalitions were formed that included pacifists, civil rights advocates, liberals and members of the traditional peace churches that supported and even encouraged non participation in the war. By the end of the war, its estimated that 50,000 conscientious objectors had fled the country or assumed false identities here in the States. Again, according to estimates, another appx 250,000 never registered (a federal offense) and 110,000 burned their draft cards.