In 2004, the military began court-martials of several military members deployed to Iraq for mistreating prisoners and detainees. Several members claimed that they were only following the orders of military intelligence officials. Unfortunately (for them), that defense won't fly. The mistreatment of prisoners is a crime under both international law, and the Uniform Code of Military Justice (see Article 93 Cruelty and Maltreatment).
It's clear, under military law, that military members can be held accountable for crimes committed under the guise of "obeying orders," and there is no requirement to obey orders which are unlawful. However, here's the rub: A military member disobeys such orders at his/her own peril. Ultimately, it's not whether or not the military member thinks the order is illegal or unlawful, it's whether military superiors (and courts) think the order was illegal or unlawful.
Take the case of Michael New. In 1995, Spec-4 Michael New was serving with the 1/15 Battalion of the 3rd infantry Division of the U.S. Army at Schweinfurt, Germany. When assigned as part of a multi-national peacekeeping mission about to be deployed to Macedonia, Spec-4 New and the other soldiers in his unit were ordered to wear United Nations (U.N.) Helmets and arm bands. New refused the order, contending that it was an illegal order. New's superiors disagreed. Ultimately, so did the court-martial panel. New was found guilty of disobeying a lawful order and sentenced to a bad conduct discharge. The Army Court of Criminal Appeals upheld the conviction, as did the Court of Appeals of the Armed Forces.
What about an order to participate in a dangerous mission? Can the military legally order one to go on a "suicide mission?" You bet they can.
In October 2004, the Army announced that they it were investigating up to 19 members of a platoon from the 343rd Quartermaster Company based in Rock Hill, South Carolina, for refusing to transport supplies in a dangerous area of Iraq.
According to family members, some of the troops thought the mission was "too dangerous" because their vehicles were unarmored (or had little armor), and the route they were scheduled to take is one of the most dangerous in Iraq.
According to reports, these members simply failed to show up for the pre-departure briefing for the mission.
Can they be punished for this? They certainly can. An order to perform a dangerous mission is lawful, because it's not an order to commit a crime. Under current law, and the Manual for Courts-Martial, "An order requiring the performance of a military duty or act may be inferred to be lawful and it is disobeyed at the peril of the subordinate. This inference does not apply to a patently illegal order, such as one that directs the commission of a crime."
In fact, if it can be shown that one or more of the soldiers influenced others to disobey, they may find the crime of Mutiny, under Article 94 added to the list of charges. Mutiny carries the death penalty, even in "peace time."
So, to obey, or not to obey? It depends on the order. Military members disobey orders at their own risk. They also obey orders at their own risk. An order to commit a crime is unlawful. An order to perform a military duty, no matter how dangerous is lawful, as long as it doesn't involve commission of a crime.