sentences:  Marshals had the common law-based power to enlist any willing civilians as deputies for necessary assistance in the execution of their duties.In the Old West this was known as forming a posse, although under the Posse Comitatus Act, they could not use military troops in uniform representing their unit or the military service for law enforcement duties.However, if a service member was off duty, wearing civilian clothing, and willing to assist a law enforcement officer on their own behalf, it was acceptable.