Shorter Pat Roberts
Assume that he is correct in stating "None of those briefed have called the program illegal or have asked for it to be halted. Criticism comes from those whose knowledge of the program begins and ends at newspaper headlines." (He isn't, but that's a separate matter).
If it's true, this is a powerful argument for a fuller public disclosure regarding the nature of the program. If the only people criticizing it are uninformed, the solution is not to blow smoke, but to inform us. Hold hearings. Explain to us all why the program is good.