Yes, and not only would Rove have to have "knowingly" made a false statement, but the false statement must be "material" to the subject matter of the investigation.
If it were definitively established that Rove did not know Plame was a "covert" agent or that her status was classified, then arguably it is not "material" when or how Rove made the statements to Cooper about her, since Rove's statements could not amount to a crime in any event.
If it were definitively established that Rove did not know Plame was a "covert" agent or that her status was classifiedSince her status was not classified...
Excellent point. I suspect that is where Libby's testimony is most significant.
That's why this case, which even my conservative colleagues likened to the Martha Stewart matter, really isn't anything close to that case. Martha was nailed for hiding the fact that she received inside information. That inhibited prosecution of her source. But there never was any doubt that the underlying act - insider trading - was a crime.
By contrast the case against Rove, et. al. relies entirely on whether Plame was in fact known to be a covert agent at the time of her *outing*. That's a tough, tough sell given the reality of her job at that time, and other easily-obtainable information on her.