The NSA is forbidden to 'target' American citizens, green-card holders or companies for surveillance without an individual warrant from a judge.

In late 2003, the Bush administration reversed a long-standing policy requiring agents to destroy their files on innocent American citizens, companies and residents when investigations closed.

NSA surveillance is a complex subject - legally, technically and operationally.

As digital communications have multiplied, and NSA capabilities with them, the agency has shifted resources from surveillance of individual targets to the acquisition of communications on a planetary scale.

The surveillance of ordinary people is far greater than I would have imagined and far greater than the American public has been able to debate.

I'm obviously an American citizen. My parents are American citizens. But I'm not looked at as an American.