It's a shame that people truly misunderstand the privacy issue. I don't know the exact number but I would imagine that a good portion more than 99% of the American population are ever going to do anything illegal or immoral that would justify the expenditure of a system like prism in order to identify them as a suspect. It's more than likely the present might be listening to the conversation that you had during and affair not that additional security.
While in principle I strongly believe in the Bill of Rights in the constitution however the practical matter is some system like prism exists it's probably going to exist in the blackness of the federal government and we may or may not have her know that it exists ever again. However little Johnny has nothing to worry about because when he stole the little bicycle pump from the kid down the street he's not going to prison.
In fact I would argue the counterargument. The spying systems are actually in our advantage. As corporate business performs corporate espionage and steals from each other and harms the American people all for the sake of the almighty profit this openness actually creates the great equalizer to make sure that the American public are protected from evil companies.
So the counter counter argument is it's actually in the best interest of American business with their deep pockets to protect the American people from the ubiquity of systems like prism.
I suppose the profit motive trumps national security.