From what I have read, Kagan seems a bit wishy-washy on the First and Second Amendments. Not sure what she thinks about the rest of the Constitution, but I think she is of the "I know better than those dead guys" school of thought.
Now I see Redstate has located her Princeton thesis on Socialism. Of course, she was just a kid then. People grow and learn and evolve...with real world experience.
Also, see Komrade Kagan