We have not fully illuminated the question of FISA warrant renewals in the case of Carter Page. There are not many experts in the law and practice of FISA warrants writing for the public. Hugh Hewitt is one of the few. He drew on his knowledge and experience for the Washington Post column “The Nunes memo revealed a damning omission.” He then returned to the subject at his site with the help of an FBI veteran with relevant experience. These are valuable contributions to understanding the possible irregularities in Page’s case.
We turn to our reader and former FBI man to provide orientation in the basics:
A FISA renewal does NOT require “NEW probable cause.” A moment’s reflection would show how unreasonable that would be–that would be like a high jump event, in which the bar keeps getting raised. What it DOES require is a showing that, based upon the original probable cause that led to issuance of the warrant, the FISA is productive. Which is to say, the intelligence that is being gathered from the FISA warrant is consistent with what the original application stated you believed you would gather (i.e., what you had probable cause to believe you would gather).
So in the case of Carter Page, a USPER, the FBI had to show probable cause that Page was engaged in clandestine intelligence activity. Therefore, they also had to show that they would likely be gathering intelligence to support that probable cause belief from the targeted communications. That’s not NEW probable cause, it’s simply confirmation that your original probable cause was correct and that you are reasonable in wishing to continue the process of collection through FISA. If the intel they’re gathering is consistent with the application, they get a renewal. If for some reason it’s not, it means their probable cause has been shown to be incorrect as regards the collection (i.e., at a minimum the targeting has been misdirected).
Hugh Hewitt discussed this issue briefly in his interview with Devin Nunes, without getting into the details above. Nunes said he had read the renewal applications and seen NO EVIDENCE that any intelligence re Trump’s circle was gathered. My educated guess is that if the Carter Page surveillance wasn’t yielding intelligence on the Trump circle it wasn’t yielding intelligence on anything. After all, the FBI already had wall to wall coverage of the Russians generally–they never needed the Page FISA to supplement that EXCEPT for targeting the Trump circle.
It is not enough to show that Mr. X is an agent of a foreign power. Lots of people are agents of foreign powers. Not only is that not per se illegal (as Professor Yoo correctly states), but it doesn’t suffice to get a FISA warrant on a USPER. This section is from a longer document that is used for internal FBI training purposes. This 16-page document gives you all you need to know about FISA. In relevant part it states in “…Probable Cause to Believe What?” at page 3, the probable cause for FISA on an USPER like Carter Page: probable cause “to establish that a US Person is conspiring with or aiding and abetting someone engaged in sabotage, international terrorism or clandestine intelligence activities.”
Let me emphasize the guidance provided in the linked summary on the relevant provisions of the Foreign Intelligence Surveillance Act.