Desertion
The number had reached about 8,000 by the first quarter of 2006. Almost all of these soldiers deserted within the United States. There has been only one reported case of a desertion in Iraq. The Army, Navy, and Air Force reported 7,978 desertions in 2001, compared with 3,456 in 2005. The Marine Corps showed 1,603 Marines in desertion status in 2001. That had declined to 148 by 2005.

Penalties: Before the Civil War, deserters from the Army were flogged; after 1861, tattoos or branding were also used. The maximum U.S. penalty for desertion in wartime remains death, but this punishment was last applied to Eddie Slovik in 1945. No U.S. serviceman has received more than 24 months imprisonment for desertion or missing movement after September 11, 2001.
A U.S. service member who is AWOL/UA may be punished with non-judicial punishment (NJP) or by court martial under Article 86 of the UCMJ for repeat or more severe offenses. Many AWOL/UA service members are also given a discharge in lieu of court-martial.

The 2012 edition of the United States Manual for Courts-Martial states that:Any person found guilty of desertion or attempt to desert shall be punished, if the offense is committed in time of war, by death or such other punishment as a court-martial may direct, but if the desertion or attempt to desert occurs at any other time, by such punishment, other than death, as a court-martial may direct.

Legal status of desertion in cases of war crime: Under international law, ultimate "duty" or "responsibility" is not necessarily always to a "government" nor to "a superior", as seen in the fourth of the Nuremberg Principles, which states:The fact that a person acted pursuant to order of his Government or of a superior does not relieve him from responsibility under international law, provided a moral choice was in fact possible to him.
Although a soldier under direct orders, in battle, is normally not subject to prosecution for war crimes, there is legal language supporting a soldier's refusal to commit such crimes, in military contexts outside of immediate peril.
In 1998, UNCHR resolution 1998/77 recognized that "persons [already] performing military service may develop conscientious objections" while performing military service. This opens the possibility of desertion as a response to cases in which the soldier is required to perform crimes against humanity as part of his mandatory military duty.
The principle was tested unsuccessfully in the case of U.S. Army deserter Jeremy Hinzman, which resulted in a Canadian federal immigration board rejecting refugee status to a deserter invoking Nuremberg Article IV.

See also: Barratry (admiralty law)
Canada and Iraq War resisters
Conscientious objector
Decimation (Roman army)
Defection
Draft evasion
Green Cadres
List of Iraq War resisters
Mutiny
No call, no show, in civilian employment
Nuremberg Principle IV
Resistance Inside the Army
Running the gauntlet
War resister

Notes: 

References: 

Works cited: 

Further reading: David Cortright. Soldiers in Revolt: GI Resistance During the Vietnam War.  Chicago: Haymarket Books, 2005.
Charles Glass. Deserter: The Last Untold Story of the Second World War.  Harperpress, 2013.
Maria Fritsche. "Proving One's Manliness: Masculine Self-perceptions of Austrian Deserters in the Second World War". Gender & History, 24/1 (2012), pp. 35–55.
Fred Halstead. GIs Speak Out Against the War: The Case of the Ft. Jackson 8. New York: Pathfinder Press, 1970.
Kevin Linch. "Desertion from the British Army during the Napoleonic Wars".  Journal of Social History, Vol. 49, No. 4 (Summer 2016), pp. 808–828.
Peter Rohrbacher.   "Pater Wilhelm Schmidt im Schweizer Exil: Interaktionen mit Wehrmachtsdeserteuren und Nachrichtendiensten, 1943–1945".  Paideuma: Mitteilungen zur Kulturkunde, no. 62 (2016), pp. 203–221.
Jack Todd. Desertion: In the Time of Vietnam. Boston: Houghton Mifflin Harcourt, 2001.
Chris Lombardi. I Ain’t Marching Anymore: Dissenters, Deserters, and Objectors to America’s Wars. New York: The New Press, 2020.

External links: 
Missing movement Archived 31 December 2015 at the Wayback Machine from About.com
Memorial to German World War II deserters in Ulm, Germany at the Sites of Memory webpage
Memorial to all deserters in Stuttgart, Germany at the Sites of Memory webpage
AWOL Information Archived 6 April 2015 at the Wayback Machine