The quote above isn't the only one that supports this analysis. Greenwald reproduces another paragraph that Snowden wrote to reporter and documentary filmmaker Laura Poitras early in their correspondence, characterizing it as "the crux of what he viewed as his mission." Snowden wrote:

The shock of this initial period [after the first revelations] will provide the support needed to build a more equal internet, but this will not work to the advantage of the average person unless science outpaces law. By understanding the mechanisms through which our privacy is violated, we can win here. We can guarantee for all people equal protection against unreasonable search through universal laws, but only if the technical community is willing to face the threat and commit to implementing over-engineered solutions. In the end, we must enforce a principle whereby the only way the powerful may enjoy privacy is when it is the same kind shared by the ordinary: one enforced by the laws of nature, rather than the policies of man.

I may be forgetting about a statement or series of statements that Snowden made over the last year. But as best I can remember, these are the clearest passages that we have indicating a second primary motive. Snowden was trying to reach the masses to inform us and spark a debate that somehow reined in the NSA.

He was also trying to reach elites. In leaking, he hoped to inform and influence a small subculture of tech influencers. Regardless of how Americans reacted to his leaks, he hoped they'd awaken to the ideology and reach of the surveillance state, and that at least some programmers would be inspired to thwart it with technology.

This is in keeping with statements Snowden has made about the importance of encryption. It also casts additional doubt on the theory that he's been a Russian spy all along. If that were true, why would he fabricate this other rationale in private correspondence with Poitras? With that, I'm going to delve back into Greenwald's text. I'm guessing there will be more of interest in future posts, and I'll update this one if I come across another relevant passage, or if anyone sends me an old Snowden quote that is relevant to this second motive for leaking.