Obviously an aggressive public relations campaign, led not only by Trump himself but also by lawyers Rudy Giuliani and Jay Sekulow, was a key. Trump never backed down from his insistence that he was innocent of all wrongdoing and that the whole was nothing but a witchhunt. In other words, as Devin Nunes said yesterday in response to the question, When did Mueller know he had no case:
"Likely since [the moment] he walked in the door [took charge] of the phony investigation."
A correspondent has sent me a Reuters article that addresses the question of Trump's successful resistance to an interview. Unfortunately, the article--The Mueller interview that wasn't: how Trump's legal strategy paid off--is short on legal analysis. My view, which shouldn't come as any surprise, is that the lack of probable cause for a legitimate investigation was key.
Consider: Team Mueller was only authorized to investigate an alleged conspiracy to collaborate illegally with Russian intelligence operatives--an alleged conspiracy that was supposed to have been conducted by an "enterprise" group of "four Americans" (Page, Papadopoulos, Manafort, and Flynn) as a subset of the Trump campaign. That was Crossfire Hurricane, which Team Mueller was authorized to continue. That means that, just as James Comey three times stated to Trump, Trump was never actually the subject of the substantive investigation:
The new legal team pressed Mueller to show them that the investigation had reached a stage that would justify sitting down with the president, a source familiar with the negotiations said.
“Are you in a position where you have evidence of a crime?” the source said the team asked Mueller.
The Trump legal team argued that because the special counsel had amassed a wealth of information through interviews with White House staffers and others close to the president, Mueller had not reached the high bar necessary for a sit-down interview with Trump.
“By providing all the witnesses from the White House and the documentation from the White House and the presidential election committee, my view from the outset was the predicate had not been reached to demand an interview with the president,” Sekulow said. “I never thought we should modify from that.”
Now, what reason could there be for Team Mueller to force or even to request a busy POTUS to submit to a lengthy interview for which, in the nature of things, he would need to prepare extensively? Absent documentable connections between Trump and the "four Americans"--connections having to do with the substantive investigation which was Crossfire Hurricane--Trump was really no more than a bystander. Any interview would be conducted on the merest of speculative bases.
Was there ever such a documentable connection? The overwhelming likelihood is: No, there never was, for the reason that Lee Smith points out:
Mueller knew that he wasn’t ever going to find “collusion” or anything like it because all the intercepts were right there on his desk.
What Smith is saying is that Team Mueller already had all the FISA surveillance that had been conducted by the FBI on the Trump campaign. Not only that, but they also had (probably illegally) all the communications of the Trump Transition, not to mention other internal emails and communications--mountains of documentation. As we have seen Mueller admit, after examining all the documentation and conducting 500 interviews, there was NO EVIDENCE of collusion. As Smith says, if there was no smoking gun or even suggestive evidence in all that documentation, there never was going to be any way to find "collusion." A presidential interview in such circumstances could only be a "fishing expedition" or "witchhunt."
The upshot was that, as Trump personal defense lawyer Jay Sekulow stated, Team Mueller lacked a solid legal basis for demanding an interview of Trump:
“We were prepared from the outset in the event of a subpoena to challenge it,” Sekulow said. “We felt confident the law was clearly on our side.”
Although not all experts agree, the legal team’s view was that a president cannot be compelled to testify unless the information could not be obtained from other sources and the circumstances were extraordinary.
The only way, then, to get Trump to submit to the intended perjury-trap interview was through the pressure of political or public opinion. And that's where the efforts of Trump, Giuliani, and Sekulow were so important--as well as the investigations of HPSCI and the efforts of conservative media and internet activists.
But what about obstruction of justice? Team Mueller was authorized to investigate obstructin of their continuation of Crossfire Hurricane. Was Trump's PR campaign obstruction? Barr and Rosenstein have basically laughed that notion off. However, there is a point in the Reuters article that suggests that Team Mueller attempted to advance the theory that the firing of Comey might have been obstruction. The Reuters article makes no bones about the Trump response:
Trump’s lawyers would not entertain questions on the issue of whether Trump had tried to obstruct justice when he fired former FBI director James Comey, then overseeing the Russia probe, and frequently assailed Attorney General Jeff Sessions publicly for not ending the inquiry.
The legal team did not think a president could be found guilty of obstruction of justice for firing someone whom he had appointed in the first place to work for the administration.
“That was off the table,” and negotiations with Mueller continued on answering questions on Russia’s interference in the election, the source familiar with the matter said.
Was that issue seriously advanced by Team Mueller? It's difficult to be certain, but we can be sure of new AG Bill Barr's views on that score. In Barr's 19 page legal analysis, which he submitted to Rod Rosenstein on June 8, 2018, Barr strongly presented the standard view that the Team Mueller theory--if that was their theory--was inadmissible. Of interest is that, in response, Rosenstein did state that that theory was no under consideration.
[Re Barr's legal views, cf. also A Message Of Hope and If Confirmed, Barr Will Be The Attorney General In Full.]
Again, the upshot could only be that all avenues for forcing an interview were closed off. Absent successful persuasion or an overwhelming marshalling of public opinion, a perjury trap interview of the president would occur only over the dead bodies of Trump's lawyers.