Attorney General William Barr – who hopes to release Mr Mueller’s nearly 400-page report this week – said last month the special counsel investigation “did not establish” that members of the Trump campaign conspired or coordinated with the Russian government.
Yet Frank Montoya, a former senior agency official with experience in counterintelligence, said the words “did not establish” are commonly used in national security cases as language merely ruling out a chargeable criminal offence.
“It doesn’t mean a subject is innocent. It means investigators didn’t find enough evidence to charge a crime,” he told Reuters.
Mr Montoya said it should fall to Congress to decide whether conduct discovered by Mr Mueller’s team warranted an effort to remove the president from office. “History suggests the impeachment process does not rely on establishing wrongdoing beyond a reasonable doubt,” he said.
According to the attorney general’s summary, no criminal conspiracy between Moscow and the Trump campaign was established. Yet court statements by members of by the special counsel’s team and evidence disclosed in various prosecutions by his office suggest lawmakers could yet reach a different conclusion.
On Sunday Jerrold Nadler, the chairman of the House judiciary committee, claimed the full report may still reveal “proof of very bad deeds”. The Democrat said “we should see and judge for ourselves”.
The most recent indication that the special counsel might document a possible conspiracy came during a closed-door court hearing in Washington DC on 4 February.
Prosecutor Andrew Weissmann said Mr Mueller was still investigating interactions between former Trump campaign chairman Paul Manafort and his Russian business partner Konstantin Kilimnik as critical to the inquiry.
“This goes to the larger view of what we think is going on, and what we think the motive here is,” said Mr Weissmann, according to a transcript released days later that indicated Mr Mueller might be on the verge of discovering new evidence. “This goes, I think, very much to the heart of what the special counsel’s office is investigating.”
Mr Mueller’s team initially claimed Manafort shared political polling data from the campaign with Mr Kilimnik, who the special counsel has said had ties to Russian intelligence.
However, three weeks after Mr Weissmann made his comments, Mueller’s office backtracked and said it needed to correct its assertions about Manafort’s interactions with Mr Kilimnik. Partially redacted court filings indicated the correction may relate to the polling data.
The special counsel’s full report is expected to be released later this week, with parts redacted by Barr to protect certain sensitive information.
Mr Mueller has charged 34 people and three Russian entities. He convicted or secured guilty pleas from a series of Trump aides including Manafort, Flynn, Cohen and Papadopoulos, and has also charged Russian intelligence officers.
Additional reporting by agencies