The other issue is what did Rove tell the FBI agents during any pre-grand jury interviews?
Even though it wasn't under oath, the charge of making a false statement to a federal official carries the same penalty as perjury (10 years in prison).
The false statement law, IIRC, doesn't have the same material issue caveats the perjury law does. Even a falsehood about something immaterial to the case is enough to hang an indictment.
We'll see what Fitzgerald has when he shows his cards.
But it stll has the same issue regarding intent. I am not sure I agree with about materiality.