Around 1980, the Marine Corps introduced the "L.I.N.E." fighting system. Line (according to Wikipedia) means "Linear Infighting Neurological Override Engagement." However, everywhere else on the internet, it is referred to as "Linear Involuntary Neurological Override Engagement." Either way, the meaning is the same. LINE fighting is a fighting system that is down, dirty, brutal and deadly.
LINE fighting is a system that works off the basis of "most painful damage possible with the least amount of movement." This means that a Marine with full combat gear (Flak Jacket, Kevlar helmet, boots, rifle, and etc.) can subdue an enemy. Now when subdue is used, it is a broad term. It can mean disarming an enemy or killing that enemy with your bare hands. While it is highly effective, it was only taught once or twice to Marines, but was the basis for the new Marine Corps hand-to-hand combative system, known as the Marine Corps Martial Arts Program or MCMAP.
L.I.N.E. was designed for results that ranged from severe body pain and disfigurement to death.