Mr. Pickering was targeted by a longtime surveillance system called mail covers, but that is only a forerunner of a vastly more expansive effort, the Mail Isolation Control and Tracking program, in which Postal Service computers photograph the exterior of every piece of paper mail that is processed in the United States — about 160 billion pieces last year. It is not known how long the government saves the images.
More:Together, the two programs show that snail mail is subject to the same kind of scrutiny that the National Security Agency has given to telephone calls and e-mail.
The program has led to sporadic reports of abuse. In May 2012, Mary Rose Wilcox, a Maricopa County supervisor, was awarded nearly $1 million by a federal judge after winning a lawsuit against Sheriff Joe Arpaio, known for his immigration raids in Arizona, who, among other things, obtained mail covers from the Postal Service to track her mail. The judge called the investigation into Ms. Wilcox politically motivated because she had been a frequent critic of Mr. Arpaio, objecting to what she considered the targeting of Hispanics in his immigration sweeps. The case is being appealed.