The University of Ottawa law professor was back on Parliament Hill on Wednesday, with the same message, at the first of a series of NDP-sponsored public hearings on the Harper government's massive budget implementation bill.
"I come here in a non-partisan nature because I'm worried about the state of Canadian democracy under this present government," Mendes told the hearing.
How to get Canadians equally concerned about it is another matter.
The NDP is hoping their hearings will help raise public awareness and rally public opinion against the budget bill, which is stuffed with a host of non-budgetary measures including overhauls of immigration, Old Age Security, Employment Insurance, environmental assessment and fisheries management laws.
The NDP, along with other opposition parties, maintain it's a "Trojan Horse bill" designed to push through a bunch of controversial measures with little public notice or parliamentary scrutiny.
But the Liberal experience suggests it's no easy task to engage Canadians about the state of their democracy.
Liberal-sponsored hearings two years ago were similarly focused on Harper's attempts to avoid parliamentary scrutiny, although in that case the party was protesting the prime minister's use of prorogation to shut Parliament down altogether.
The erosion of parliamentary democracy was a favourite theme of former Liberal leader Michael Ignatieff.
Indeed, Liberals defeated Harper's minority government last spring on a contempt-of-Parliament motion. During the subsequent election campaign, Ignatieff repeatedly exhorted Canadians to "rise up" against what he described as Harper's "ruthless, relentless disrespect" for Parliament.
The Liberals were reduced to a third-party rump for their efforts and Harper won his long-sought majority.
"I think, in some respects, it takes time for the public to really know and understand what's going on," Mendes said in an interview.
"But ultimately, the dangers to Canadian democracy will eventually seep through and people will say, 'Well, hang on a second here. Yeah, we care about jobs and we care about the economy but didn't we fight two wars for something else?'"
Mendes said disrespect for Parliament has increased under majority Conservative rule, with Harper essentially running a "one-man government."
"He started that in a minority government, using all the tricks of the trade, from manipulating committees to prorogation to you know what and, now, it's extreme ... Canadians need to know about that. It goes way beyond the budget."
Government House Leader Peter Van Loan, meantime, disputed that assertion, saying the budget bill reflects the views Canadians expressed through "the most extensive round of pre-budget consultations ever."
"The NDP should stop obstructing this job creating bill and holding up a critical economic plan that will continue creating jobs for Canadian families," Van Loan said a statement.
Wednesday's NDP hearing attracted about 100 people, primarily New Democrat MPs and their staffers.
But Matthew Carroll, campaign director for Leadnow.ca, said 20,000 Canadians have signed an online petition against the budget bill, launched by the online advocacy group just a week ago.
"Never before has a budget been used as cover for such a sweeping agenda to remake Canadian society," Carroll said.
"The most egregious element of the bill, to my mind, is its overarching anti-democratic nature ... Such sweeping changes to our laws must be presented openly for debate."
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