(1) the NSA must be able to detect, identify, and trace people who are involved in threats to state security or criminal acts on basis of their communications
(2) one of the main (and indispensible) tools in such work is social network analysis, i.e. who talks to whom and how often. If people communicate a lot, or if they communicate little but highly significantly then they form a social network and are probably working together
(3a) you don't have the ability to detect and identify social networks on basis of communication unless you have the ability to collect metadata from anyone (i.e. you install technical means to tap everything)
(3b) it's impossible to reliably detect and identify social networks on basis of communication alone without actually using those taps to collect all metadata from everyone.
(4) therefore having reliable detection capabilities and not hoovering everyone's metadata are mutually exclusive.
(5) So unless you allow the NSA unrestricted collection of metadata (including that of all Americans), you prevent the NSA from doing its job
You can agree or disagree with him here (and you're invited to do so) but you either refute this line of reasoning or you accept that you are preventing the NSA from doing its job.
And unless you can refute this reasoning, you end up deciding whether or not to give up certain liberties (i.e. online privacy) in order to gain security. The point being that you will run an additional risk unless you give up those liberties.
Now that's a decision the voters can and should make I think. After all, they're the real stakeholders, not the organizations.