How Trump officials' encrypted messaging made Mueller's job harder

While Robert Mueller’s report didn't conclude that President Trump conspired with Russia during the 2016 campaign — nor did it reach a definitive conclusion that Trump obstructed justice — it pointed to a particular obstruction to Mueller's work: encrypted messaging.

In a summary section of the report detailing why the special counsel’s office did not find collusion, Mueller says that some of the people his office interviewed or investigated used messaging apps that feature encryption, which deletes messages after a certain period of time.

This, Mueller said, prevented investigators from corroborating witness statements and questioning witnesses about inconsistencies.

“Given these identified gaps,” the report states, “the Office cannot rule out the possibility that the unavailable information would shed additional light on (or cast in a new light) the events described in the report.”

Read more: The Mueller report makes a damning case that Trump obstructed justice .

Deeper in Mueller’s report there are windows into what sort of information slipped from his grasp. Perhaps most tantalizing to investigators was the potential for more detail concerning the Trump campaign’s apparent effort to weaken the Republican Party platform on the question of U.S. aid to Ukraine.

The report details an Aug. 2, 2016, meeting between Paul Manafort, Trump’s then-campaign manager, and Konstantin Kilimnik, a Russian citizen suspected by the FBI of having ties to Russian intelligence. Kilimnik had earlier aided Manafort’s lobbying work for Ukraine’s Russia-aligned government. According to Mueller, the August meeting concerned a peace plan in Ukraine that would favor Russian interests in the east of the country, where separatists have been waging a war since 2014. Mueller goes on to state that while he did not find that Manafort passed information about a peace plan to Trump or his campaign, investigators were also not able to access some of Manafort’s communications with Kilimnik that followed the Aug. 2 meeting because messages were exchanged using encrypted apps.

Mueller is clear that Manafort seemed interested in hiding the nature of his talks with Kilimnik: A federal judge, the report notes, later found Manafort lied to the special counsel’s office about the discussions.

The law enforcement official whose firing spurred the special counsel’s investigation in the first place is likely incensed over this revelation. James Comey, who led the FBI for four years until Trump abruptly removed him in May 2017, had made the threat of encrypted messages a central issue of his tenure.

“We cannot break strong encryption. I think people watch TV and think the bureau can do a lot of things,” Comey complained to Congress in 2015. “Even if I get a court order under the Fourth Amendment to intercept that communication as it travels over the wires, I will get gobbledygook.”

Read more: The Mueller report's biggest revelations about Trump

At the time, Comey was contending with the threat of ISIS attacks in the U.S., and his bureau was struggling to contain a flow of Americans leaving the U.S. to join ISIS in Syria. The FBI had watched as communication between ISIS recruiters and curious Americans moved out of its reach. The group’s use of encryption made it different, Comey said, from the “al Qaeda of old,” which carefully vetted and groomed recruits for spectacular attacks that took years to plan.

Instead, ISIS recruiting was ad hoc, and its early stages strangely public. “ISIL will find the live ones on Twitter and we can see them say, ‘Here is my encrypted mobile messaging app. Contact me there,’” Comey testified, using an alternative acronym for the terrorist group. He went on to say that Congress needed to work with telecom companies to allow law enforcement some way to peer in.

Comey’s testimony to the Senate Select Intelligence Committee came a year after ISIS established its so-called caliphate in parts of Syria and Iraq, and as worry was growing about attacks inside the U.S. In May that year, two gunmen attempted to storm an exhibit near Dallas featuring cartoons of the Prophet Muhammad. ISIS claimed the attackers as their own, and the FBI examined social media connections between the shooters and the group.

Trump campaigned in 2016 on eradicating ISIS, and after expanding U.S. military operations in Syria and dramatically upping bombing activity, is now claiming victory.

The tools ISIS once used are still out there, of course, and terrorism experts worry sleeper cells in Iraq and Syria are waiting to reconstitute. But the Mueller report shows Comey’s encryption crusade had more immediate ramifications — preventing a full accounting of the biggest question surrounding an American president in decades.

“The tools you’ve given us are not working the way you expect them to work in the highest-stakes matters. I need help figuring out what to do about that,” Comey told Congress four years ago.

Mueller, who oversaw the start of the post-9/11 era as FBI director, might have new reason to agree.

Cover: Paul Manafort arrives for a hearing at US District Court on June 15, 2018 in Washington, D.C. (Photo by BRENDAN SMIALOWSKI/AFP/Getty Images)