Washington (CNN) Trump lawyer Rudy Giuliani has started saying something interesting -- and totally irrational -- in interviews this week: That President Donald Trump's decision on whether to sit down with special counsel Robert Mueller depends, at least in part, on what information the Justice Department hands over in what the President has taken to calling "Spygate."

"We want to see how the briefing went today and how much we learned from it," Giuliani told Politico's Darren Samuelsohn on Thursday of the Justice Department's briefings for a handful of lawmakers on an informant's work in 2016. "If we learned a good deal from it, it will shorten that whole process considerably."

Rudy Giuliani says that an ultimate decision won't be made on whether President Donald Trump will sit for an interview with Special Counsel Robert Mueller until "the details of this 'Spygate' situation" are figured out.

That decision, though, will apparently hinge on whether Trump is given whatever report is produced following a Justice Department probe of the FBI's use of an informant to learn about his campaign's contacts with Russia. Trump demanded the review on Sunday following a coordinated effort by his Capitol Hill allies and conservative media to discredit the informant.

"Are we going to get a report on 'spygate'?" Giuliani said, using the term Trump invented this week.

That is amazing/appalling.

Let's remember that Trump has invented the idea that the FBI authorized a "spy" to be embedded in his 2016 campaign out of whole cloth. No source familiar with the FBI's operations says anything like that happened. What did happen is that the FBI had suspicions about contacts between two Trump advisers -- Carter Page and George Papadopoulos -- and Russian officials. So they used a longtime confidential source to talk to the two men -- as a way to suss out what the Russians might be up to.

There is no "Spygate." Not based on the available facts. (Rep. Adam Schiff, ranking Democrat on the House Intelligence Committee said this on Thursday after being briefed about the confidential sources by DOJ officials: "Nothing we heard today has changed our view that there is no evidence to support any allegation that the FBI or any intelligence agency placed a spy in the Trump campaign.")

To use a trumped-up -- ahem -- controversy as a negotiating tool for a presidential interview in an investigation in which five people (including Trump's deputy campaign chairman and his national security adviser) have already pleaded guilty is a remarkable move.

The Point : Giuliani continues to go back and forth as to whether Trump will sit down with Mueller. But to use the carrot-and-stick approach to extract supposed information on a conspiracy theory that the President has convinced himself of is a new low.