Attorney General Holder refuses to answer question on whether the WH was collecting information on members of Congress and Supreme Court Justices

The amazing video if a great question by Senator Kirk is available here.  How is Holder not able to answer this question by Senator Kirk (R-IL).  Here is my transcript of the video.

Kirk: "Mr. Attorney General, I want to take you to the Verizon scandal and -- which I understand takes us to possibly monitoring up to 120 million calls. You know, when government bureaucrats are sloppy, they're usually really sloppy. Want to just ask, could you assure to us that no phone inside the Capitol were monitored of members of Congress that would give a future executive branch, if they started pulling this kind of thing off, would give them unique leverage over the legislature?" 

Holder: "With all due respect, Senator, I don't think this is an appropriate setting for me to discuss that issue. I'd be more than glad to come back in a -- in an appropriate setting to discuss the issues that you have raised.  But in this open forum I don't . . ." 

Kirk: "I would interrupt you and say the correct answer would be say no, we stayed within our lane, and I'm assuring you we did not spy on members of Congress.". . . 

Mikulski: "We are going to stop here because this fully briefed is something that drives us up the wall."