I posit that you're not seeing a failure of representative democracy to properly express what is a position with majority support. Rather, you're failing to perceive the nature of the electorate.
I remember I stared college the year after 9/11 and was in school when the Iraq war started. Conservative place as far as colleges go, but left of center for the region as a whole. I heard a lot of talk about turning the middle east into a glass parking lot. That was not a position anyone was afraid to take publicly. Imagine my surprise when I'd come back to my very liberal circle in northern Virginia and hear about the "overwhelming public opposition to the Iraq war." Simply put, ideological minorities often don't realize that they are that.
There's stuff that gets votes, and there's stuff the majority supports. They aren't necessarily the same.
On the other hand, the Washington Post/Pew Research Center say there's narrow majority support some of the mass surveillance. Narrow majority opposition for some aspects: http://www.washingtonpost.com/politics/most-americans-suppor...
There are very few candidates who oppose mass surveillance (though we did elect a president who spoke out against trading freedom for security during his campaign), and most of them also have a bunch of other policy positions that are sufficiently distasteful to enough people that even opponents of mass surveillance will either reject him/her for those other positions, or reject him/her for being "unelectable".