nsa leaker edward snowden facing tough questions from last week tonight's john oliver. he traveled to moscow to meet snowden and conducted the toughest interview with snowden since he conducted nsa spying activities. >> how many of the documents have you actually read? >> i evaluated all of the documents in the archive. >> you read every single one? >> i understand what i turned over. >> there is a difference between understanding what's in the documents and reading what's in the documents. >> i recognize the concern. >> because when you are handing over thousands of nsa documents, the last thing you want to do is read them. "the new york times" took a slide and did not redact it properly and in the end, it was possible to see something was