Ordinary Geiger counters, worn on belt clips and resembling pagers, have been in use by the U.S. Customs Service for years.

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.

Scores of armed antigovernment groups, some of them far more radical, have formed or been revived during the Obama years, according to law-enforcement agencies and outside watchdogs.

For personal use, I recommend the free and open-source Truecrypt, which comes in flavors for Windows, Mac and Linux.

I don't say I never use Facebook, but I often think about closing my account.

Snowden grants that NSA employees by and large believe in their mission and trust the agency to handle the secrets it takes from ordinary people - deliberately, in the case of bulk records collection, and 'incidentally,' when the content of American phone calls and e-mails are swept into NSA systems along with foreign targets.