The newly minted Liberal leader intends to introduce a motion that would strip party whips of their power to decide which MPs are allowed to make members' statements in the House of Commons.
Trudeau's motion will put Harper's legendary iron control over his caucus to the test, providing an outlet for restless Tory backbenchers to defy their leader.
Indeed, Harper may be trying to buy himself some time to strike a truce with his backbench rebels before letting Trudeau's motion come to a vote.
The motion was to have been debated and put to a vote on Monday, a Liberal opposition day. But an hour after Trudeau gave notice Friday of his motion, Government House leader Peter Van Loan announced a sudden change in next week's Commons agenda, bumping the Liberal day to Wednesday.
The Tory caucus meets Wednesday morning and Van Loan's move gives Harper another chance to try to quell the uprising before the debate.
The Commons will now consider an anti-terrorism bill on Monday, which Van Loan indicated has taken on urgency in the wake of the Boston bombing.
Liberals aren't buying the rationale.
"I am skeptical," said Liberal MP Marc Garneau, noting that the anti-terrorism bill has been wending its way through the Commons for more than a year.
The bombings in Boston occurred on Monday yet Garneau said Van Loan made no mention of the anti-terrorism bill when he made his weekly statement Thursday about next week's House business. It took on "monumental proportions" only after the Liberals gave notice of Trudeau's motion, he said.
Harper spokesman Andrew MacDougall chimed in on Twitter:
"Grits bleating because oppo day moved back 2 days so House can pass the 'Combating Terrorism Act'. Seriously."
The motion is undoubtedly problematic for the prime minister, who is facing a rebellion by backbenchers fed up with their inability to speak their minds during the daily 15 minutes allotted for members' statements.
The revolt was triggered last month when British Columbia MP Mark Warawa was removed from the Tory roster because he intended to talk about abortion — an explosive subject which divides Conservatives and which Harper is determined to keep a lid on.
Warawa has asked Speaker Andrew Scheer to rule that his privileges as an MP were breached; at least eight other Conservative MPs have openly backed his complaint.
The Liberals, who were in the midst of a leadership contest until last Sunday, have not weighed in on the issue until now.
Indeed, some aggrieved Conservative backbenchers have complained about the lack of support they've received from opposition parties.
But Trudeau, who made democratic reform the centrepiece of his successful leadership bid, intends to remedy that with his motion.
It calls on MPs to support changing the rules governing members' statements.
Instead of the current practice of having party whips supply the Speaker with a list of MPs approved to make statements on any given day, the motion would require the Speaker to recognize MPs in alphabetical order, by party. MPs would be able to trade their speaking orders, providing some flexibility for those who might be out of town when their turn comes up or who want to urgently address an issue in their ridings.
Independent MPs would be considered as a group, in alphabetical order.
A majority vote of MPs is all that is required to change the rules of procedure for the Commons, so Trudeau's motion could have real effect if it is passed, pre-empting Scheer's ruling on Warawa's complaint.
In a statement Friday, Trudeau said his motion is aimed at ensuring Parliament is more representative of the views and priorities of Canadians.
"Members of Parliament from all parties should be community leaders, free to share the priorities and express the views of those they represent," Trudeau said.
"Canadians must have confidence that the candidates they elect will represent their views in Ottawa, not Ottawa’s views to them."
The motion is consistent with Trudeau's leadership campaign promise to empower MPs.
He has said a Liberal government would allow its backbenchers to vote as they see fit on all bills and motions, other than those that involve a key element of the party's election platform, budget or the charter of rights.
Harper loyalists have argued that the prime minister promised Canadians he would not re-open the divisive abortion debate and is, thus, within his rights to prevent Tory backbenchers from speaking on the subject.
Conservative whip Gordon O'Connor has likened MPs to members of a sports team and maintains only the coach should decide who gets to play.
The issue erupted when an all-party committee ruled last month that Warawa's private members' motion — calling on the Commons to condemn the practice of sex-selective abortion — was non-votable, effectively killing it.
Warawa was on the Tory roster for members' statements that day but was removed once O'Connor found out the MP intended to use his one-minute statement to castigate the committee for its decision.
Earlier this week, Warawa announced he would not appeal the committee's ruling to the Speaker, which could have led to a rare secret ballot vote by all MPs. His complaint about being denied the right to speak during members' statements still stands; Scheer has not yet ruled on the matter.
The NDP has offered equivocal support to the Tory backbenchers, without recommending how the Speaker should rule. NDP House leader Nathan Cullen has said the issue doesn't really apply to his party because it does not vet its MPs' statements.
However, in the fall of 2011, the NDP temporarily stripped two of its MPs — John Rafferty and Bruce Hyer — of their right to speak in the Commons, including their ability to make members' statements. They were punished for voting against the party position in support of the now-defunct long-gun registry.
Hyer now sits as an independent.
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