Why did the Nazgul not succeed in Bree and on Weathertop?

[davem]

Originally Posted by skip spence

That is ironic. The most fearful creatures known to men scared ****less by a midget and a name. It's like a monster too afraid to come out from under a little kid's bed at night.

My take is that its not simply a 'name' - Frodo invoked Elbereth, called down her protection, & she intervened directly - or at the very least the Nazgul feared that she might do so. However powerful the Nazgul might be in M-e Varda could have squished them without a thought.