For the sake of time, here's Peggy Noonan representing my view:

From her blog:

...Because of the built-in bias in the system—the bias to do too much, to go too far—the creation of an invasive American surveillance state is probably inevitable. Politicians are people who can do math. The number of people who want to be safe, they are certain, is far greater than the number worried about abstract issues of privacy. Moreover, they figure voters are more or less like this: They’ll have their little blog debates about privacy right up until a bomb goes off, and then they’ll all go into a swivet and join a new chorus: “Why didn’t you protect me? Throw the bums out!”

There is no way a government in the age of metadata, with the growing capacity to listen, trace, tap, track and read, will not eventually, and even in time systematically, use that power wrongly, maliciously, illegally and in areas for which the intelligence gathering was never intended. People are right to fear that the government’s surveillance power will be abused. It will be. There are many reasons for this, but the primary one is that humans are and will be in charge of it, and humans have shown throughout history a bit of a tendency to play every trick and bend and break laws. “If men were angels,” as James Madison wrote, limits, checks, balances and specifically protected rights would not be necessary. But they aren’t angels. Add to all this simple human mistakes, innocent and not, and misjudgments. And add to that sheer human craziness, partisan lust, political mischief of all sorts.