I decided to watch this thread for a while before responding.
The reason being that there is often a bunch of difficulties in the terminology area. It seems somewhat worked out.
Fight drive and Rank are not dependent on one another. Much like high fight drive dogs usually show high prey drive, high fight drive is often accompanied by some rank. It doesn't mean that the dogs cannot be high in fight and not rank (I'll point out that my current dog is not rank yet very high in fight, and the dog previous was very high in fight and rank as #$%$!!, an earlier patrol dog I had...Dolf for Lou since he probably knew this dog....was very high in fight but was not rank at all). I prefer dogs of very high fight and low rank.
Now, do not forget that no drive really stands alone without some pressures from other drives and character traits, also, there is the concerns about rearing (I believe that rank issues can be grown into a dog that has the potential, very easily, and that way too many people are afraid they will decrease their young dog's potential in protection if they squash this behavior, it needs to be stopped prior to maturity for sure), and experiences as the dog grows his brain and subsequent behaviors.
I have also seen dogs labeled as rank when in fact the dogs were confused and panicked by the training (and genetic potential for this as seen in some Mink progeny) and bite because they are fearful and have low thresholds to survival behavior and have low thresholds to prey, causing the initial reaction to be in self-defense and unloading into a strange combo of overlapping drives.
OK, I hope this clears a few things up. You can have great fight and low rank, but often very extreme fight drives posses some level of rank, which is determined by both genetic potential and nurture.
Some really rank dogs have only medium to poor fight (the dog that uses rank in protection that bites his handler more than the bad guys, and when he does bite bad guys the hadler can see that the dog isn't terribly committed to the fight). Take the not uncommon image of a dog that has high rank and finishes a session of muzzle work and can't get off the field without marking (I hate these dogs).
Rank can and is directed at anyone that the dog sees within the heirachy or potentially becoming a pack member. Extreme rank (a poor trait and not of normal levels) boils over into all kinds of situations like protection and play. This is abnormal, not normal rank stuff that might be directed at the family members of a somewhat rank dog.
Donn was quoted as saying that the dogs selected for PSP are often rank, very rank. In part this was due to the limited amount the school could spend on dogs, so they got the bottom of the barrel, nasty rank critters that civilians wanted gone.
There have been some changes in their program which I will have a chance to see this fall, in part due to the fact that they breed their own dogs now according to standards designed to produce police dogs.