The National Security Agency has expedited a number of Freedom of Information Act requests in the wake of Edward Snowden's disclosures. For the book on secrecy I wrote with D.B. Grady, I sought from the agency the latest guidance on minimizing data collected on U.S. persons. It took about two years for the agency to process that request, and we published the book with only a very heavily redacted version to review.
Today, via email, an agency FOIA officer sent me a much cleaner copy of USSID 18 (USSID stands for United States Signals Intelligence Directive). Most of the redaction text has been restored. The NSA also provided Annex J, which spells out how the NSA can collect data on international narcotics traffickers even if one side of the communication is inside the United States.
In the Snowden cache, a smaller, more concise version of this document that the Justice Department provided to the Foreign Intelligence Surveillance Act court is already circulating, and you can read it here. It's dated 2009.
The guidelines I've obtained date from 2011. The Director of National Intelligence has already begun to revise the manual, which is classified at the SECRET level, with access to Special Intelligence compartment required.
They spell out the process for "emergency" monitoring without approval — 72 hours is given before the attorney general must personally sign off on a new target, or the surveillance is terminated and the collected signals are thrown out.
The guidelines say that the "selector terms" chosen for interception must "reasonably be likely" not to result in the interception of communications of a U.S. person — regardless of that person's location.
Every communication that passes through a channel with one terminal inside the United States must be subject to a screen for U.S. persons of some sort, unless that communication occurs on a channel used exclusively by a foreign power. This requirement can be waived by the analyst for two hours; the director of the Signal Intelligence Directorate has to give formal approval for additional collection without a screen.