Congress has a need to know.....they just can't be trusted.
Since they control the budget, they do get oversight......they also leak like crazy and do more damage to the security of this country then anything else.
However, your lefty idiots in congress are obsessed with the CIA, they'll get off the NSA with no problems.
"Since they control the budget, they do get oversight......"
Oversight does not mean that they get to know what's going on, except in very general terms.