Who is Levin in the novel, Young Jane Young?

Levin is a democratic congressman. He is married to Embeth, but starts an affair with Aviva. Levin is smart, confident, and hardworking. He is charming, and able to talk his way out of messy situations, so that his career does not end with the affair. He plays the antagonist for most of the novel, though he does not necessarily turn out to be truly evil in the end.