most US LEO, Prison, and military dogs are german shepherds, and a lot of malinois but not as many as gsd's. almost all, if not all, are european imports. though that includes pups born from european imports parents, grandparents, etc.
there are actually quite a few working quality dogs born from german showlines. Gucci is currently the #1 working gsd in north america and he is pure german showlines. of course you are more likely to produce better working quality dogs from working line dogs, and show dogs from showlines. there is ahuge difference between german working and german showlines, but compared to american and canadian line gsd's there is almost no difference between working and showling european gsd's.
most import from europe because american show breeders are concerned with appearance which does not meet the gsd standards. there are an extremely few american bloodline gsd's that have 1/2 the working ability of mid quality european gsd's.
malinois are growing in popularity in the US among LEO and Military, but the gsd is still on top. I imagine the gsd will probably always be on top. they are larger and more intimidating for one thing. The malinois started being used by leo agencies because gsd's had a serious hip and elbow problem. this has pretty much been taken care of (not saying hip displasia is not found in gsd's anymore) because leo's began importing higher quality dogs.
when I was 5 years old my dad adopted a 2 year old gsd mix from a woman he worked with. the dog had lived its 2 years tied to a post of her deck with no training or socialization. he was not dangerous, except that he was not obedient at all. my dad obedience trained him very well but the dog could never be trusted off leash...turn around for 1/2 a second and he was gone. he would jump his 7 foot fence and disappear. a friend of my dads was on the local police force and knew a officer who was looking for a canine partner. that officer adopted our gsd mix to be a police dog.
neat story but that doesnt happen anymore because they pay large but very fair prices for very high quality dogs, high qaulity temperament, high quality health, high quality wokring ability. they arent buying dogs to be uncontrollable viscious killers (incase anybody reading this now or in the future doesnt know that), they NEED the dogs to be very self assured and under complete control at all times. not just controlled on leash or when they command the dog to bite, but 100% control when they tell the dog to release a bite/stop an attack.
I don't like him.