What is Brody up to?

Every week, I watch 'Homeland' and find myself caught up in the trajectories of all kinds of sub-plots and supporting characters, only to return in the end to that same question: What is Brody trying to accomplish? Who is this secretive, seemingly tortured soldier, really? What does he want? What makes him tick?

Though the episode was titled "Representative Brody," Sergeant Nick's story line was a lot less interesting than Carrie's this week. Things had been looking up for poor Carrie, but the what-goes-up-must-come-down logic of this show demanded that she must suffer, and suffer she did. Start with the look on her face when she realized what a fool she'd been to think that she and Brody might have a future together. She'd gone to the trouble of introducing a bottle of white to her desolate refrigerator and cueing up a bit of Miles Davis, and all he wanted was to make sure that she had no intention of ever telling anybody about their little weekend at the cabin. Claire Danes earned her inevitable Emmy nomination with the expression of tasered hope that crossed her face. I felt like crying for her.