There's a little-known backstory to Director of National Intelligence James Clapper's famous "not wittingly" lie, in response to Sen. Ron Wyden's March 2013 question, "Does the NSA collect any type of data at all on 'millions or hundreds of millions of Americans'?" that demonstrates the importance of whistleblowers to our democratic control over the national security establishment.
The backstory is worth remembering, as Congress debates what to do about the dragnet Clapper tried to hide.
It stems from on-the-record statements Bill Binney (one of the highest-level whistleblowers to ever emerge from the NSA) made to former NSA whistleblower and historian James Bamford for a March 2012 Wired article. In addition to explaining that the collection points for President George W. Bush's illegal wiretap program, Stellar Wind, were positioned to collect domestic data, Binney revealed that the US had access to "AT&T’s [and Verizon's] vast trove of domestic and international billing records, detailed information about who called whom in the US and around the world." Binney also explained how the NSA can suck up targeted content from around the world using something like a Google search in a program we have since learned is called XKeyscore.
Four months later, NSA Director Keith Alexander donned a hacker costume and spoke at the DefCon hacker's conference in Las Vegas. DefCon Founder Jeff Moss asked General Alexander about Binney's claims. "Does the NSA really keep a file on everyone?" "Absolutely no," Alexander responded. "Anybody who would tell you that we’re keeping files or dossiers on the American people knows that’s not true."
Less than a year later, Edward Snowden would provide proof that Alexander's response - not Binney's original claim - was the false statement.