Final answer:
A soldier is considered to be failing the ABCP when they do not meet the required body fat standards set by the Army.
Step-by-step explanation:
A soldier is considered to be failing the Army Body Composition Program (ABCP) when they do not meet the required body fat standards set by the Army. For example, if a soldier's body fat percentage exceeds the allowable limit for their age, gender, and height, they would be considered to be failing the ABCP. This can be determined through body composition assessments such as the Body Mass Index (BMI) and the Army Tape Test.