. >> michelle van cleave was america's top counterintelligence officer. national intelligence, she was in charge of coordinating the hunt for foreign spies from 2003 to 2006. >> the chinese are the biggest problem we have with respect to the level of effort that they're devoting against us versus the level of attention we are giving to them. >> the chinese have stolen technology used in the space shuttle and in submarine propulsion systems. in the late 1990s, a congressional commission found that china now holds the most closely guarded secrets america had. >> we learned, and the cox commission reported, that the chinese had acquired the design information for all u.s. thermonuclear weapons currently in our inventory. >> make sure i understand. the chinese are in possession today of the designs of all of our nuclear weapons? >> yes. >> how did they get that? >> the questions of how they acquired it remain, to some extent, unknown. >> how the u.s. lost its atomic secrets may be unknown, but there are fewer mysteries in the case of tai shen kuo and gregg be