In yet another reminder about increasing threats to America's IT infrastructure, a former top  cybersecurity official said the nation's critical computer networks are so vulnerable to attack that it should deter the U.S. from waging war with other nations. Richard Clarke, an adviser to the last three presidents, said at a conference this month that other countries could retaliate through devastating cyberattacks capable of destroying U.S. power grids, banking networks and/or transportation systems. Countries that could “crash” the U.S. economy include China, North Korea, Iran and Russia, he said. Plus, because the U.S. military is entirely dependent on computer systems, a war could end up with troops entering a battlefield in which “nothing works.” “I really don’t know to what extent the weapon systems that have been developed over the last 10 years have been penetrated, to what extent the chips are compromised, to what extent the code is compromised,” Clarke said. “I can’t assure you that as you go to war with a cybersecurity-conscious, cybersecurity-capable enemy that any of our stuff is going to work.” Clarke and General Keith Alexander, who heads both the National Security Agency and U.S. Cyber Command, said the solution lies in working to eliminate network vulnerabilities and more aggressively seeking out malware or viruses in American corporate, military, and government systems. Yet Clarke suggested these issues will not be fixed without broader government regulations. Plus, the U.S. should make it clear to countries like China that stealing high-tech American data will be punished, he said.