A new report from The Washington Post outlines a tool that lets the NSA record every phone call in a country for a entire month, then replays entire conversations as needed. Think of it like a DVR of every conversation that occurs over a rolling 30-day period — including any conversations involving Americans.

The retrieval tool is called RETRO, building off of a voice call collection program called MYSTIC that was introduced in 2009. According to the Post report, written by Barton Gellman and Ashkan Soltani, which combines confidential interviews with documents leaked by Edward Snowden, RETRO went into operation against an unidentified country in 2011. In other words: this program, unlikely many others, belongs solely to President Obama.

It appears to work like this. Once turned on, MYSTIC scoops up the call data — including voice data — and throws it into RETRO. Analysts can then "retrieve audio of interest that was not tasked at the time of the original call" from RETRO — meaning that they can listen to calls that weren't analyzed in real-time. (Note: it's not actually a DVR. There's no video. It's an analogy.) "Each month" analysts use RETRO to "send millions of voice clippings, or 'cuts,' for processing and long-term storage." After 30 days, content drops out of the tool, constantly being replaced by new information.

That's a ton of data to maintain. Last year, The Wire tried to figure out the physical footprint of the NSA's surveillance systems, given how much storage space is required for large amounts of data. Audio data takes up much more space than text data (and video data even more than audio). That's been a problem with RETRO, Gellman and Soltani report.

In the first year of its deployment, a program officer wrote that the project “has long since reached the point where it was collecting and sending home far more than the bandwidth could handle.”

Because of similar capacity limits across a range of collection programs, the NSA is leaping forward with cloud-based collection systems and a gargantuan new “mission data repository” in Utah. According to its overview briefing, the Utah facility is designed “to cope with the vast increases in digital data that have accompanied the rise of the global network.”

It's not clear what country served as the guinea pig for RETRO in 2011, or if it has since been extended to other nations. (The Post appears to have withheld the name of the first country.) MYSTIC is collecting phone communications in at least six countries, according to the annual intelligence budget, so it's possible that RETRO could be online in each.

It appears certain that Americans' data is collected, if they place or receive calls to or from target countries. The NSA is legally prohibited from surveilling Americans, but data and information about and from "U.S. persons" is regularly swept into the NSA's net through what it calls "incidental collection." The agency has to "minimize" the collection of Americans' data, but it's far from 100 percent. "[I]ntercepted communications 'may be retained and processed' and included in intelligence reports," Gellman and Soltani note. "The agency generally removes the names of U.S. callers, but there are several broadly worded exceptions."

Contacted for a comment, the NSA lashed out at the reporters. "[C]ontinuous and selective reporting of specific techniques and tools used for legitimate U.S. foreign intelligence activities," a spokesperson said in a statement, "is highly detrimental to the national security of the United States and of our allies, and places at risk those we are sworn to protect."