The Balrog vs The Witch King

[CSteefel]

Originally Posted by davem

Well, perhaps the Witch King could have defeated the Balrog - if he'd used a bloody great battering ram wielded by mountain trolls to stun him first.....

I think the Appendix B in Return of the King makes clear that it is really the Witch King who does this (not the battering ram):

March 15: In the early hours the Witch-king breaks the Gates of the City.

Up until this point, we mainly see the Witch King (along with the other Nazgul) using fear as their principal weapons, as is stated in the Unfinished Tales

Moreover, their chief weapon was terror.

or commanding armies, as the Witch King did in the attacks on Eriador from Angmar.

Plus, Tolkien makes specific mention of the augmentation of the Witch King's power, I just cannot find the quote at the moment.

Now whether this all translates to the ability to defeat a Balrog, I don't know. The Witch King only does pretty much what Sauron tells him to, so it would have to be a face off in which the power of Sauron comes up against the Balrog...