An anonymous reader writes with some snippets pulled from a lengthy Q&A session at The New Yorker with former NSA head Keith Alexander, in which Alexander defends the collection of metadata by U.S. spy agencies both abroad and within the United States: "The probability of an attack getting through to the United States, just based on the sheer numbers, from 2012 to 2013, that I gave you—look at the statistics. If you go from just eleven thousand to twenty thousand, what does that tell you? That's more. That's fair, right? [..] These aren't my stats. The University of Maryland does it for the State Department. [...] The probability is growing. What I saw at N.S.A. is that there is a lot more coming our way. Just as someone is revealing all the tools and the capabilities we have. What that tells me is we're at greater risk. I can't measure it. You can't say, Well, is that enough to get through? I don't know. It means that the intel community, the military community, and law enforcement are going to work harder."