The foreign powers or organizations may send such soldiers to support countries or insurgencies while minimizing the risks of potential casualties and avoiding the political ramifications of overtly mobilizing military forces to aid an ally.
The French Marquis de Lafayette and the Prussian Baron von Steuben offered key assistance to the Continental Army during the American Revolutionary War of 1775–1783.
"[3] During the Spanish Civil War, Germany deployed a large number of 'volunteers', also known as the Condor Legion, to serve as mercenaries and pilots to assist the nationalist forces.
The Army has performed advisory missions to increase the capability and capacity of foreign militaries from the Philippine Insurrection at the beginning of the 20th century to more recent conflicts in Vietnam, Iraq and Afghanistan.
These soldiers and Marines live with their Afghan and Iraqi counterparts (often in very austere and stoic[clarification needed] conditions) in remote combat outposts often a great distance away from any U.S. or coalition support.
Special Forces and Navy SEALS also work with ANA/ASF or with the Iraqi Army, but the bulk of combat advisors are infantry and combat-arms soldiers and Marines.
The combat advisor mission requires US officers and NCOs to teach, coach and mentor host nation (HN) security force counterparts.