>>I know that many Democrats want to cling to the belief that, in Perlstein's words, "the powers that be will find it very easy to seize on this one error to discredit [my] NSA revelation, even the ones he nailed dead to rights". Perlstein cleverly writes that "such distraction campaigns are how power does its dirtiest work" as he promotes exactly that campaign.

How in the world could he make this mistake? Are the five slides the only ones he has out of the 40,000 documents that refer to PRISM? Why hasn't Snowden directly commented on this issue, or even better; why didn't Greenwald contact him when this issue came up?

I do think he jumped to conclusions based ont the slide; but the truth is, it isn't a closed issue. Intelligence sources and company executives sources continue to give somewhat differing answers about exactly what PRISM is or does. Some suggest that Greenwald got it about right the first time and it really is capable of pulling data on demand from company servers. Simply saying that PRISM is just a GUI interface doesn't rule out the possibility that such an 'active' data source is closely associated with the program.