"I don't think it's enthusiasm for McCain, I think it's [fear] of Obama,"?

Brackets in a quote mean that the word was inserted by the writer to make the quote’s meaning clearer, as any given quote is usually taken out of context.

Can also mean ‘emphasis mine’ or in other words the article writer did insert that word to make the whole context more clear.
Good show Hobbes.

cheerz

The brackets do indicate an editorial change of the word, possibly for clarity or grammatical word agreement.

You have nothing to fear but fear itself. At least Obama won’t try to run the country by making us fear everything. (Rove’s Rules of Order)

Nice, Galileogirl!

“fear” of a black man…

I wonder what the original word use was…

Is that actually from an article? That’s a very strange word to replace in a quote. Usually editorial word replacements are for specifying pronouns or modifying verb agreement…