She's not going to be able to sue the government (again).
She's not able to go after the BIG money (Fox), because they didn't do squat until after she was fired, and then they mostly broadcasted a message in her favor.
So she's going after Breitbart.
Oh, and now she's -definitely- a public figure, and hence is now open to all the slings and arrows of conjecture.
In my opinion, and I got an A in my Media Law class back in college, her case is VERY hard to prove.
1) The chain of custody of that clip is going to emerge - What happened with that video between the meeting it was shot at, who shot it, who edited it, and when it hit Breitbart's inbox? HOW did it get there?
2) A key factor any any libel or slander suit is the presence of malice. Did Breitbart take something, and set out to smear her? They'll need to figure out #1 above... Can she prove that Breitbart edited it? I doubt it. And that would HAVE to be there for malice to stick.
What I'm wondering is if someone put together this thing as a campaign to be launched on purpose. Scary, huh? Edit up the tape, and email it from a throwaway... Then sit back, and watch the New Black Panthers get knocked off the scene. Any lawsuit is just peripheral fallout.