The Military Selective Service Act (MSSA) and government regulations recognize two types of conscientious objectors:

CONSCIENTIOUS OBJECTORS TO ALL FORMS OF MILITARY SERVICE:
These are persons, who, by reason of religious, ethical, or moral belief, are “conscientiously opposed to participation in war in any form.” These people may be honorably discharged from military service. In the event of a draft, they are exempt from military service. If called up, they may perform alternative service as civilians.

NONCOMBATANT CONSCIENTIOUS OBJECTORS:
These are persons who, by reason of religious, ethical or moral belief, are conscientiously opposed to killing in war in any form but who do not object to performing noncombatant duties (such as being a medic) in the armed forces. These people are reassigned to non-combatant duties in the Armed Forces or, in the event of a draft, are trained without weapons and assigned to noncombatant service.

The MSSA and government regulations do not recognize the following type of conscientious objection:

SELECTIVE CONSCIENTIOUS OBJECTION (SCO):
These are persons whose consciences will not permit them to participate in what they believe to be an “unjust” war but would permit them to participate in what they believe to be a “just” war. For example, somebody might refuse to fight in Iraq, believing it to be an unjust or immoral war, but would not be opposed to fighting in a war of defense. Selective conscientious objection is NOT legal, and an SCO would face jail time.