This is an anonymity problem: The NSA cannot create a dossier on you from your metadata unless it knows that you made the calls the agency is looking at. The privacy question is all about data-gathering: Should the NSA have access to nationwide metadata? The right answer to that question is yes. But identities should be hidden.

Suppose the NSA had access to all the metadata of every call a certain person made over the past five years — but didn’t know who that person was. Instead, the NSA knew only that individual “H4QQ9F” made the calls in question. In that world, there’s no Orwellian surveillance.

But suppose that individual H4QQ9F made a call to a known al-Qaeda safe house in Yemen. Then the NSA should be permitted to pierce the veil of anonymity and find out who H4QQ9F is.

Privacy was key when the question was whether, or how much of, our private lives could be monitored or recorded. That train has left the station. Today, most of us allow a great deal of our lives to be monitored and recorded — whenever we use a search engine, for example, or buy something online. Even the content of our private communications, such as e-mails and chats, is now routinely exposed to and stored by people at Facebook or Google. The key question isn’t how to keep information about us from getting out into the world; it’s how that information can be used.