Diego Gambetta:

Given the huge political costs if an attack of the scale of 9/11 were to be repeated, it makes sense for policymakers to be overzealous in issuing public warnings.

Senator Dianne Feinstein, of California:

They will come after us, and I think we need to prevent an attack wherever we can.

Senator Chuck Grassley, of Iowa:

If it can happen in Paris, it can happen in New York again, or Washington, D.C.

Alison Smale:

Even as governments are ramping up their counterterrorism efforts, they are igniting a growing debate about whether they are going too far, too fast, and are at risk of sacrificing civil liberties as they scramble to intensify security. The trade-offs are not always easy to discern ...

Samuel Moyn:

"It ought not to be beyond the intelligence of even the most hidebound local politicians to see the benefits of imaginative compromise," Tony Judt says. Yet so far, it has been.

Michael S. Schmidt:

The revelation by the D.E.A. shows how tactics that began as a response to terrorism have become part of the government's approach to more routine crimes.

Senator Patrick Leahy, of Vermont:

I am deeply concerned about this kind of suspicionless intrusion into American's privacy in any context, but it is particularly troubling when done for routine criminal investigations.

Mathangi Krishnamurthy:

Things can rarely be erased these days. We leave signs of our presence everywhere and all signs are under observation. There is no starting over. Our histories are in code, and all our secret pleasures open to scrutiny. We must not write anymore except when things we write are not worth scrutiny.

David Bernstein:

There's no way to test the merit of ideas unless someone is willing to criticize them, sometimes harshly.

Kelly Fitzsimmons, co-founder of the Hypervoice Consortium:

What would it mean to have a corpus of conversations after there is regime change, and a new government doesn't like what you said?