As the Commons committee studying the SNC-Lavalin affair seems to have been put on ice, the Senate is wrestling with whether it should launch its own inquiry on the matter.

But there is a battle brewing between Independent and Conservative senators on what exactly the scope should be for such a study, nearly two months after allegations of inappropriate pressure first surfaced.

While a Conservative motion proposes calling former justice minister Jody Wilson-Raybould to the Senate's legal and constitutional affairs committee, a new Independent plan for a special committee proposes the focus should now shift to the wider issue of prosecutorial independence and bifurcation of the attorney general and justice minister roles.

Independent Quebec Sen. André Pratte, appointed by Prime Minister Justin Trudeau, said there may not be much more to learn from Wilson-Raybould after her extended committee appearance and the release of documents and a recording. But, the Senate "should not sit on the sidelines while fundamental questions on the administration of justice in this country are being asked," he said.

The focus, rather, should be how to protect the government's top lawyer from political pressures in the future, Pratte said.

He is proposing a committee be quickly constituted so that it can meet and study the issue and then report back to the Senate by no later than June 1 — a very tight timeline.

'A different, more neutral, senatorial approach'

"The [Conservative] hope is obviously to continue to embarrass the government," Pratte said.

"On the other hand, the government's aim is to put an end to the controversy. Our objective, as an independent Senate, should be neither to prolong nor to stifle the scandal but to provide a thorough review of the facts ... we should suggest a way forward — a different, more neutral, senatorial approach."

The former La Presse journalist-turned-senator said "the facts are now out in the open," and thus the special committee he is prepared to launch should not be tasked with investigating what happened in this SNC-Lavalin matter alone.

"Rather, it should reflect on what it all means and what lessons we should learn from what happened. Was the pressure put on the attorney general inappropriate or not? What principles can we use to reach a conclusion? In future, is it possible to pinpoint the rare circumstances in which the attorney general can intervene with the Public Prosecution Service?"

Pratte said deferred prosecution agreements (DPAs), also known as remediation agreements, the legal tool at the heart of this matter, should also be studied by the proposed Senate committee.

Pratte's proposal faced criticism from the Conservative opposition.

"Middle ground? More like a farce. The Trudeau Senators have dined out for 3 years on putting on a big show. This is no different. This is a smoke screen by the [Independent Senators Group] just like the one by [the Prime Minister's Office]," Conservative Quebec Sen. Leo Housakos tweeted.

"This is again another example of the games that are being played in this chamber in order to circle the wagons, to defend the prime minister who has done something the Canadian public and the press for weeks have been calling upon him to respond to clearly and unequivocally," Housakos said in the chamber on Thursday.

The Conservative opposition in the upper house, led by leader Larry Smith, has sought to supplement the Commons justice inquiry with a wide-reaching investigation of their own at the Senate's legal and constitutional affairs committee.

Smith's motion featured a long list of potential witnesses, including the prime minister himself, but also Trudeau's chief of staff, Katie Telford, and eight others.

That plan has faced head-winds from some Trudeau-appointed Independent senators and the government's representative in the upper house, Peter Harder, who say such an inquiry would be consumed by partisanship and that a study is best placed for a Commons committee composed of elected parliamentarians. Indeed, Harder introduced amendments that gutted the motion for an inquiry. Tories say this opposition is equally partisan in that it shields the government from further scrutiny.

But Smith withdrew his motion Thursday in favour of another Tory proposal, from Conservative Sen. Don Plett, the party's whip. That motion suggests calling Wilson-Raybould alone as a witness, a potentially more workable plan with only eight weeks left of Parliament before it rises for the summer recess.

Conservative Manitoba Sen. Don Plett has a competing motion that calls on Wilson-Raybould to be a witness at the Senate's legal and constitutional affairs committee. (Sean Kilpatrick/Canadian Press)

Pratte sought to head off government opposition to his committee proposal — or the suggestion that this Senate body would simply duplicate the study by former Liberal justice minister Anne McClellan — by saying the other work underway on this issue is to be conducted largely in secret.

"Ms. McLellan is not Parliament. Her advice to the prime minister will undoubtedly be very valuable, but many heads are better than one. Moreover, she will not do her work in public as a Senate committee would do, thereby educating both the public and parliamentarians on these complex issues," Pratte said.