The road taken by Justin Trudeau to his Senate reform decision

Just three months ago, Justin Trudeau and the Liberals dismissed as "ridiculous" an NDP motion calling on the Grits and Conservatives to expel unelected senators from their respective caucuses.

Yet the Liberal leader did just that Wednesday, surprising everyone, particularly his party's 32 senators who'd been kept entirely in the dark about his plans.

Trudeau's abrupt about-face left rival parties, cynics and conspiracy theorists to speculate that the move was motivated by the need to distance himself from senators who could be tarred with making inappropriate expense claims in an imminent interim report by auditor general Michael Ferguson.

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But insiders involved in the decision-making process insist the truth is much more prosaic: expulsion was the only concrete action the leader of the third party could take that wouldn't involve re-opening the Constitution or potentially be derailed by the Supreme Court, which is expected to rule sometime this year on the constitutional requirements for reforming or abolishing the upper house.

Looming audit

At no point, they maintain, did the looming AG's report which Ferguson's office says it has shared with no one factor into the equation.

For that matter, neither did the NDP motion. Trudeau's contention last October that the motion was unconstitutional was based, insiders say, not on the expulsion of senators from party caucuses but on other aspects of the motion, which presumed to dictate how Senate resources could be used and to limit senators' travel.

In a bicameral parliamentary democracy, one chamber can not tell the other chamber how to conduct its business.

As for the timing of Trudeau's bombshell announcement, that was strictly a case of wanting to start the new year with a bang.

Aggressive stance on Senate

According to insiders, who spoke on condition of anonymity, the genesis of Trudeau's dramatic move was a meeting of his tight-knit inner circle before Christmas to frankly evaluate what went right and what went wrong in 2013.

Those involved including national campaign co-chairs Katie Telford and Dan Gagnier, principal adviser and longtime friend Gerald Butts, chief of staff Cyrus Reporter and national Liberal director Jeremy Broadhurst marvelled at how the Senate expenses scandal had dominated the federal political scene for most of the year, almost to the exclusion of anything else.

They concluded that Trudeau who'd been painted as a defender of the status quo while the Conservatives championed an elected Senate and the NDP banged the drum for abolition needed to be more aggressive about reforming the Senate.

Trudeau was willing but laid down two conditions: He would not propose anything that would require a constitutional amendment, with all the attendant, divisive wrangling with the provinces that would entail.

Nor did he want to simply promise to do something if elected prime minister one day; he wanted to be able to "walk the walk" a tall order for the leader of the third party, who has zero legislative power.

Inner circle met with academics, experts

His inner circle consulted discreetly with more than a half dozen political scientists and constitutional experts.

One of them, University of Waterloo political scientist Emmett Macfarlane, impressed upon them that they needed to be very careful not to propose anything that might run afoul of the Supreme Court, which he warned could well rule that anything that fetters the prime minister's discretion to appoint whomever he pleases to the Senate would need a constitutional amendment, approved by at least seven provinces.

Based on those discussions and inspired partly by an op-ed article penned by former Ontario cabinet minister Greg Sorbara, Trudeau's adviser proposed an independent process for nominating worthy, non-partisan Senate appointees, similar but more open and transparent to the process used to choose recipients of the Order of Canada.

Trudeau, who'd already floated the idea of seeking independent advice on Senate nominees, was agreeable.

But he pointed out that the proposal was just a promise of future action and, moreover, did nothing to address the fact that the Liberal caucus currently included 32 highly partisan senators.

He wanted to do something concrete, as he had done last spring when he announced that Liberal MPs and senators would voluntarily begin disclosing more details about their travel and hospitality expenses.

Pushing out senators seen as only way

His advisers ultimately concluded that booting Liberal senators from caucus was the only measure that would meet the leader's criteria.

The decision was a closely guarded secret.

Senators, many of whom have devoted decades of service to the Liberal party, were not consulted for fear of Trudeau's move leaking out.

But he did them the courtesy of meeting with them privately Wednesday for a half hour, personally delivering news of their immediate expulsion from caucus before making the announcement publicly.

His close advisers were well aware some senators would be hurt and angry.

They were pleasantly surprised to find about half the senators instantly applauded Trudeau's news, while the rest eventually came round after a couple of hours talking among themselves and getting over their initial shock.

His advisers were also aware that once the senators were cut loose, Trudeau would no longer be able to control how they might choose to regroup or how the Senate would deal with 32 suddenly independent senators.

New 'Senate Liberal caucus' unpleasant surprise

Still, they were unpleasantly surprised when the senators decided to reconstitute themselves as the Senate Liberal caucus and to continue designating themselves as Liberal senators a move that contradicted Trudeau's assertion that there are "no more Liberal senators" and gave fodder to rival parties to dismiss his move as a meaningless gimmick.

They were even more surprised, and angered, when Senate Speaker Noel Kinsella agreed to recognize the 32 as Liberals.

Kinsella's decision flies in the face of convention, Trudeau's advisers maintain, noting that whenever a senator has been expelled from caucus in the past, they have been forced to sit as independents.

Kinsella's ruling suggests senators Mike Duffy, Pamela Wallin and Patrick Brazeau expelled from the Conservative caucus over allegedly fraudulent expense claims and subsequently suspended without pay from the Senate could still call themselves Tory senators.

Trudeau's team believes Kinsella, a Conservative senator, was motivated by a partisan desire to embarrass the Liberal leader. Nevertheless, they see no point in trying to reverse his decision.