Six months after exposing the NSA's secret surveillance program, Edward Snowden sat down with a Washington Post reporter, and over meals of burgers, pasta, ice cream and Russian pastries, explained that his personal mission has already been accomplished.

“I already won," he told the Post's Barton Gellman, one of the reporters he initially approached with the leak. "As soon as the journalists were able to work, everything that I had been trying to do was validated. Because, remember, I didn’t want to change society. I wanted to give society a chance to determine if it should change itself.”

Snowden told Gellman that he tried to alert superiors at the NSA as far back as three years ago, when he found security flaws as a system administrator and recommended the agency switch to a two-man authorization for administrative access.

He also talked about meeting with superiors and co-workers to air his concerns in October, 2012, when he demonstrated the massive volumes of data being collected on Americans with a heat map called BOUNDLESSINFORMANT.

And when nothing changed, he turned to the media. According to Gellman, Snowden began speaking with reporters as early as December, 2012, but waited until April to begin passing information along.

“All I wanted was for the public to be able to have a say in how they are governed,” Snowden said.

At the same time, the NSA was collecting information on hundreds of millions of internet users through the PRISM program, while simultaneously monitoring phone calls and hacking information from the same internet companies with the UK's GCHQ in a program called MUSCULAR.

Snowden says this blind bulk data collecting is his biggest problem — he believes that individual targeting based on probable cause would be more appropriate.

“I don’t care whether you’re the pope or Osama bin Laden... As long as there’s an individualized, articulable, probable cause for targeting these people as legitimate foreign intelligence, that’s fine. I don’t think it’s imposing a ridiculous burden by asking for probable cause. Because, you have to understand, when you have access to the tools the NSA does, probable cause falls out of trees.”

Intelligence officials, for their part, say that enemy targets like Al-Queda have changed their communication methods in the aftermath of the NSA revelations.

They're also concerned over whether China or Russia downloaded the full archive from his computer, and whether Snowden could have a "dead man's switch," set to release documents if he disappears or dies. (When asked, Snowden said that sounded "more like a suicide switch.")

The NSA's incoming director Rick Ledgett estimates Snowden could have more than 1.7 million files — a much higher number than previously estimated.

That could also prove to be Snowden's saving grace: Ledgett has said that he would be interested in offering Snowden amnesty in exchange for “assurances that the remainder of the data could be secured.”