Consider the possibility that others have come forward and leaked documents, which have then gone on to be published (perhaps even by Greenwald et al) with sour

Consider the possibility that others have come forward and leaked documents, which have then gone on to be published (perhaps even by Greenwald et al) with sources listed as "NSA documents obtained by $publication". Everyone would assume they came from Snowden without much question giving excellent cover for other leakers who want these things to be known but aren't willing to give up drastically above average salaries in tropical locations to do so.