Seven Questions: Waiting for a Cyber Pearl Harbor

I'm not a fan of Clarke but he makes a good point here in Foreign Policy:
Chinese hackers are growing increasingly bold in probing critical U.S. defense networks. But former U.S. counterterrorism chief Richard A. Clarke tells FP that if the United States waits for a dramatic, 9/11-style attack on its critical infrastructure to act, it will be missing the real threat.
Foreign Policy: Last year, a Pentagon computer network serving Defense Secretary Robert M. Gates was hacked into, allegedly by the Chinese military. Do you think the Chinese military was behind the attacks, and if so, what was it trying to accomplish with these attacks? (go here for Clarke's answer and the rest of the article)