In 2013, in the early days of the Snowden leaks, Harvard Law School professor and former Assistant Attorney General Jack Goldsmith reflected on the increase in NSA surveillance post 9/11. He wrote:
Latest in PATRIOT Act
According to the Office of the Director of National Intelligence, the National Security Agency will no longer access the historical metadata collected under Section 215 after the 180-day transition period authorized under the USA Freedom Act. The Agency will retain the information for three additional months (so, until sometime in late February 2016) to allow technical personel to evaluate the integrity of data from the new collection method, but it will be off limits for analytical purposes.