The line of questioning that seems to provoke the strongest defensive reaction and gets cut off as rapidly as possible is the one that would eventually lead to the question of whether any of this surveillance (data mining in particular) has been used by any political figures to surveil their political opponents (whether inside or outside an administration).

sPh

I was thinking exactly the same thing. With so few people "read in" on these programs, the opportunity for abuse is there for the taking. Sadly, I wouldn't be surprised if this administration took advantage of it. Nixon's cohorts bugging the DNC sets a precedent.