Diane Lockhart is the top litigator at Alicia's law firm. She offers to mentor The Good Wife's main character on the show's first episode.
While Alicia doesn't fully accept, Diane appears to be someone on whom she can rely.
Diane: Do you believe her?
Will: I believe a lot of things I can't prove.
You have some very prominent baggage. But, hey, if [Hilary Clinton] can do it, so can you.Diane