Proc92 said:
They will require a subpoena, then fight the subpoena, and then refuse to testify claiming some form of intelligence based prohibition, then assert the 5th. Brennan won't testify on any relevant issue.
I see it a bit differently. A grand jury subpoena means there is a sitting grand jury investigating the matter and the possibility that Brennan and Clapper are the targets suddenly gets very very real.
The only way to fight the subpoena (which has been approved by the federal judge overseeing the grand jury's actions) would be a Motion for a Protective Order that would set parameters for such testimony. (Limited attendance, in a SCIF, transcript sealed until later, invocation of CIPA procedures)
A Motion to Quash won't work to avoid testifying, IMO. I don't care how classified or top secret Brennan and Clapper want to yammer about. We have procedures for those.
Only way to avoid testifying completely is invoking the 5th. Period.