Before Jody Wilson-Raybould could state her case to her ex-cabinet colleagues on Tuesday, she first had to make her case directly to the prime minister.

And so, on a frosty Ottawa morning, Wilson-Raybould and her former chief of staff, Jessica Prince, walked into the prime minister's West Block offices for a private meeting with Justin Trudeau, his chief of staff, Katie Telford, and Clerk of the Privy Council Michael Wernick.

It was the morning after Gerald Butts had publicly announced his resignation as Trudeau's principal secretary. The very apex of the Liberal government was reeling — and now Wilson-Raybould wanted to walk into the cabinet room a week after she had walked out of cabinet.

Her pitch was simple. She wanted to explain her side of the SNC-Lavalin affair to the inner circle she had quit on February 12.

Trudeau eventually agreed to bring her request to the full cabinet. Ministers debated the matter for two hours while Wilson-Raybould waited outside.

Multiple sources tell CBC News that some cabinet ministers were concerned about the optics of letting Wilson-Raybould attend a meeting of the inner circle just a week after she'd quit cabinet.

They eventually consented to Wilson-Raybould's unprecedented appearance but — as Wernick revealed in his extraordinary testimony before the Commons justice committee this week — Attorney General David Lametti left the cabinet room to avoid any potential conflict.

No apologies

Sources described WIlson-Raybould as unapologetic during her cabinet room appearance. People inside the room, and those later briefed on the conversation, confirm that Wilson-Raybould told the cabinet she felt she had been pressured improperly to help SNC-Lavalin, something first reported by the Globe and Mail.

Jody Wilson-Raybould has been clear that she's ready to tell her side of the story in the SNC-Lavalin scandal. But what's standing in her way? Salimah Shiviji explains the complex situation. <a href="https://t.co/3s9tAGs1Ma">pic.twitter.com/3s9tAGs1Ma</a> —@CBCTheNational

The specifics of what Wilson-Raybould said in cabinet were not shared with CBC News, but Wernick's testimony likely shed some light on what was said. The clerk typically attends cabinet meetings, and Wernick was at this one.

"I predict that the former attorney-general will express concern to this committee about three events. The first is the meeting with the prime minister," Wernick told MPs on the justice committee Thursday.

"The second is a conversation between the Prime Minister's Office staff and her former chief of staff when she was minister of justice on Dec 18. And the third is a conversation that I had with her in the afternoon of Dec. 19."

Wernick's testimony was a broad defence of the conduct of the government he serves. His arguments have done nothing to resolve the partisan debate surrounding the SNC-Lavalin controversy.

But that particular bit of testimony helped clarify the timeline of the key fracture points that led to Wilson-Raybould's resignation from cabinet and Butts' departure as the prime minister's top adviser.

What did the staffers say?

Wernick corroborated the prime minister's account of the Sept. 17 meeting with Wilson-Raybould. He said Trudeau asked for the meeting to discuss the slow pace of legislation central to the government's Indigenous reconciliation agenda. When Wilson-Raybould asked Trudeau about SNC-Lavalin, Wernick said, the PM assured his then-attorney general that any decision was hers to make.

​"He indicated that it was entirely her call to make, that she was the decider," Wernick testified. "And that is a message the PM conveyed to the minister on every situation that I'm aware of that came up."

There were no politicians at the Dec. 18 meeting — just political staff. A senior government official confirms the meeting was between Prince, Butts and Telford.

There has been no public account of this meeting, but a source tells CBC News that whatever transpired is crucial to Wilson-Raybould's argument that she was improperly pressured.

If that's the case, then Wernick's call to Wilson-Raybould the very next day would have been especially unwelcome.

"I conveyed to her that a lot of her colleagues and the prime minister were quite anxious," Wernick said to the committee. "There were a lot of people worried about what would happen, the consequences, not for her, the consequences for the (SNC-Lavalin) workers and the communities and the suppliers."

Many senior Liberals feel Wernick did a good job of defending the government's conduct in the SNC-Lavalin controversy. They argue the clerk was able to do what the prime minister should have done from the beginning: lay out, in plain language, the case for significant government action to protect 9,000 SNC-Lavalin jobs while also respecting the rule of law.

Others aren't so sure. CBC News has learned that, when a group of cabinet ministers met for a regular gathering at Environment Minister Catherine McKenna's Ottawa Centre home on Thursday night, one of the issues they discussed was an assessment of the fallout from Wernick's testimony.

A 'strong basis' for investigation

Some critics have described Wernick's comments as overly partisan. The Conservatives suggest they form the basis of a police investigation.

​"There is certainly a strong basis to be made for an RCMP investigation," Conservative MP Michael Cooper said Friday. "I think that what the evidence of Mr. Wernick before the justice committee confirms is that the allegations of political interference in the prosecution of SNC Lavalin are supported."

Meanwhile, Liberal backbenchers remain largely in the dark about the specifics of what happened — and what might happen next.

Several Liberal MPs told CBC News they are convinced Wilson-Raybould is determined to bring down the prime minister and this entire controversy is a way to settle scores over being demoted to Veterans Affairs. They hold that view even though Wilson-Raybould assured the Liberal caucus on Wednesday that she was on the Liberal team and supports the Liberal agenda.

Other caucus members believe her motives are more personal than that. They praise Wilson-Raybould as extremely principled while also criticizing her as rigid.

Only Wilson-Raybould herself can say for sure. She'll get that chance when she testifies at the justice committee next week. It still isn't clear whether the questions about how solicitor-client privilege applies to her will be resolved before her appearance.

Wilson-Raybould kept notes

What is clear is that she has an important story to tell — and it is likely to be well-documented. Multiple government sources say Wilson-Raybould is a prodigious note-taker, making copious written accounts of nearly every meeting she attends.

When she resigned from cabinet, multiple sources say, the Prime Minister's Office did a thorough vet of their own notes and records to see if there was anything that could cause them trouble. Wernick argued in his testimony that no one in PMO crossed a line

"So, I can tell you with complete assurance that my view of those conversations is that they were within the boundaries of what is lawful and appropriate," Wernick said.

At this point, it seems unlikely that Wilson-Raybould would agree.