As to whether his crime was so serious, Libby really had no way of knowing just what consequences he was setting in motion. Valerie Plame had been a covert CIA operative- (in fact, she was evidently brought home after Ames' perfidy became known for fear that she would be in danger); for all Libby/Cheney/Rove/Novak knew there were people down the line whose covers could have been blown or just possibly who could have lost their lives.