And after some initial reluctance, the government eventually fell in line with the proposal as well.
Initially, Paul Calandra — Prime Minister Stephen Harper's parliamentary secretary —echoed the sentiments of auditor general Michael Ferguson, who said the House of Commons could benefit from his comprehensive audit of the Senate without having to undergo the same level of individual scrutiny.
"I certainly wouldn't support that," Calandra said. "I think the auditor general made very clear comments that it wasn't required."
The Prime Minister's Office subsequently issued a clarification: "We support having the auditor general sit down with the board of internal economy and determining a way for him to engage on this."
The board is the secretive group of four Conservatives, two New Democrats and one Liberal, who police Commons spending. They meet behind closed doors and typically issue only cursory summaries of their decisions.
Mulcair and Trudeau were less equivocal on inviting the auditor general to scrutinize MPs' spending.
"We have already proposed it, the other parties voted against it," Mulcair said.
Mulcair appeared to be referring to an obscure dissenting committee report his party wrote two years ago, in which it backed giving the auditor general a clear legislative mandate to audit spending in the House of Commons, including MPs' expenses.
The NDP has also proposed replacing the board with an independent oversight body which would operate primarily in public.
"The NDP has every intention of getting rid of the secretive board of internal economy," Mulcair said. "Every penny being spent there is public money and the public has a right to see how every penny is spent."
Trudeau said it's high time Ferguson looked at the House of Commons.
"House leadership needs to sit down with the auditor general and figure out a way for him to engage," Trudeau said.
He stopped short of calling for a forensic audit of the Commons, but said: "It is time that we actually establish a process whereby we can restore Canadians' confidence and that means asking the auditor general to come in."
Ferguson's report on Senate expenses, tabled Tuesday, found 30 current and former senators improperly spent almost $1 million, nine of them so egregiously that their cases have been referred to the RCMP.
The Commons can and should learn from his recommendations that the Senate needs greater transparency and independent oversight of expenses, Ferguson said.
Over the last five years, more than twice as many MPs have been accused of improperly spending more than four times the amount Ferguson concluded was misspent by the 30 senators.
Among those accused are dozens of NDP MPs who've been ordered by the board to repay almost $4 million for allegedly improperly using parliamentary resources for partisan purposes.
The NDP maintains the board is a kangaroo court. The party filed a court challenge to the board's rulings last fall, but it has gone nowhere since.
In the Commons on Wednesday, as New Democrats slammed Harper for appointing some of the senators flagged for claiming ineligible expenses, Calandra repeatedly countered with demands that NDP MPs repay the money the board says they owe.
"Canadians do not differentiate. When elected officials, or any parliamentarian, have issues with expenses they expect them to pay it back," Calandra said, advising Mulcair to "take care and watch out for his ever-growing proboscis as he climbs down off of his high horse."
— With files from Kristy Kirkup
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