[Legate of Amon Lanc]

Originally Posted by Bêthberry

Aragorn's words are general enough at the Council of Elrond, yet his reference to "the one fat man" suggests the Innkeeper of the Prancing Pony, who has shown us (in passages I haven't quoted) how little he understands or appreciates Strider. I could be wrong, of course, but it seems to me that no fell creature of the Barrow Downs nor troll of the wilds could strike the uncanny fear into the hearts of men (and hobbits) that the Black Riders do; nor could they be the foes which freeze Butterbur 's heart.

I of course also don't think that a troll could strike the fear into the hearts of men - though I think the BWs could pretty well, what makes you think they would not? People are scared only by tales about the hills they live in, and all this cold grasping hearts of the hobbits... well, surely you can read for yourself and see what impression it makes.
Anyway, I certainly don't think that Aragorn would be speaking about Black Riders on the Council, because if he says:

"Strider" I am to one fat man who lives within a day's march of foes that would freeze his heart or lay his little town in ruin, if he were not guarded ceaselessly.

That certainly does not refer to the Black Riders. The "foes" are there obviously permanently (see the words used: "lives" and "ceaselessly", that would not be used for riders who have been around there for a few days). It actually, after seeing this, really makes me think more and more of the Barrow-Wights. Although like I said before, it just somehow does not go well with the impression I have of them being the "homely folk" staying in their tombs and haunting passing visitors. Also I already expressed my doubts when it comes to the power of the Rangers to stop them from invading civilised lands, if they chose to.

Originally Posted by CSteefel

One argument against this last interpretation is that in fact the Rangers were unable to keep the Black Riders from overrunning Bree. The Witch King swept the Rangers away at Tharbad, and then a few days later (after invading the Shire), swept through Bree...

A slight note (I don't want to be picky, but since you said it already for the second time ): it was at Sarn Ford, not at Tharbad. I know that in the rather unexplored wilderness south of Bree one really hardly cares, but these two places are some three days ride from each other and are something completely different. (Sarn Ford were the southern borders of the Shire, that was why the Rangers were there.)