Authority Will be Respected.

Cops are already quite intimidating themselves, military police are just *that* much more intimidating, however to at least myself, the "description guy". Marine MPs seem like the worst type of cop you could piss off with one's stupid antics. These Marines have not only responsible for external security and the transportation and care of enemy POWs, but the apprehension of Marines who threaten the mission, themselves, or others. A Marine trained to take down other Marines is something truly hard to imagine having a fun time fighting against. "I" sure wouldn't as for fear of messing about and finding out, the finding out is sure to be unpleasant. 

Since October of 1944, the Marine MPs exert authority behind all else, where a Marine MP will give life and limb in their sworn mission of protecting the mission, brothers, and sisters!