This is extremely counterproductive. You aren't going to get anywhere simultaneously bemoaning the damage caused by extremist acts and the excesses of the NSA.

When you point out the failures of the NSA to stop specific instances of terrorism, it only suggests that they need more resources and legal surveillance. The reasons for wanting the NSA surveillance to stop have to be that the innumerable injustices suffered by citizens under a surveillance state would be worse than the occasional extremist attack that would be preventable under such surveillance.

No, that's not what he is saying at all. With the maddening amount of resources ($80 billion for fuck's sake) spent on surveillance of both foreign and domestic communications, incidents where the agencies have the resources and intelligence to stop attacks but don't/can't shows that no amount of money spent or rights lost will give us absolute safety.

Yeah, it's weird what our existing civil liberties are able to prevent out intelligence agencies from doing.

If it were the Stasi, Gestapo, or NKVD that noticed an Army major communicating with a Resistance element for any reason you'd have been able to count the remainder of that major's life in hours. FBI, on the other hand, went "Meh, not enough evidence to start an investigation".

So be careful about the conclusion you draw from that. All you've really said is that we currently have handcuffs too tight on the NSA and FBI.