This data mining bullshit has nothing to do with national security, would not have prevented 911 and does nothing to keep us safer.
Period.
Know what would have prevented 911? Enforcing our immigration laws for one thing. Information sharing between agencies for another thing. And being proactive with fighting the Islamic terrorists for a third thing. You know, good old fashioned common sense and intel work.
How is storing information on millions of innocent people in a gigantic government database supposed to prevent terrorism? Please explain that to me. How did it prevent the Boston bombing? Or wait.... Our insanely suicidal immigration policy led to that attack as well. What a coincidence. I mean what are the odds?
So you see, the solution is mass amnesty for illegals and extensive data mining forever!
The next step is going to be "precrime" like in that movie Minority Report.

After they mine the data, they will predict crime before it happens. Utopia and paradise all around. With the government in charge of it all, what could go wrong?