whatever its purpose is, it isn't protection.
“We have not identified a single instance involving a threat to the United States in which the telephone records program made a concrete difference in the outcome of a counterterrorism investigation,� said the report, a copy of which was obtained by The Washington Post. “Moreover, we are aware of no instance in which the program directly contributed to the discovery of a previously unknown terrorist plot or the disruption of a terrorist attack.�
http://www.washingtonpost.com/world/national-security/independent-review-board-says-nsa-phone-data-program-is-illegal-and-should-end/2014/01/22/4cebd470-83dd-11e3-bbe5-6a2a3141e3a9_story.html