If Justin Trudeau's Facebook page is any indication, the federal Liberal party may have lost a big swath of voter support on Wednesday for helping to pass Bill C-51, the Conservatives' controversial anti-terrorism legislation.

"Bill C-51 has passed and you helped do that. My vote is now with the NDP," reads one of the hundreds of comments on the Liberal leader's page. "Too bad you sold us out to spying by supporting Bill C-51," says another, reflecting the tenor of most of the comments.

The anger could easily be dismissed as typical netizen venting. But with the New Democrats' landmark win in the Alberta provincial election a day earlier — ousting the Conservatives from power for the first time in 44 years — it could be indicative of a larger overall shift in voter mood.

Some of the commenters said they had opted against "wasting" their votes on NDP candidates in previous federal elections because of the unlikelihood of the party gaining power. They're rethinking that strategy now that the big win in Alberta makes the unlikely seem possible.

"It's more real now," says Shachi Kurl, senior vice-president of polling organization Angus Reid Institute. NDP leader Tom Mulcair "could restyle himself as a viable national alternative."

Fading support for C-51

C-51 was initially introduced in January by the Conservatives in response to the violent attacks against military personnel in Quebec and on Parliament Hill late last year. Prime Minister Stephen Harper positioned the bill, which will give more powers to the Canadian Security Intelligence Service and broadly enhance data-sharing capabilities of various law enforcement agencies, as a necessary tool to plug security holes and prevent future attacks.

The public initially supported C-51, with a February poll by Angus Reid finding 82 per cent in favour. But then the opposition piled on — the NDP and Green Party pushed for a major overhaul while Canada's privacy commissioner, the Canadian Bar Association, business leaders and civil liberties groups warned of a lack of oversight.

In March, thousands of Canadians attended protests across the country and a Forum Research poll in April found 56 per cent of respondents opposed the bill. Seventy-seven per cent of Liberal supporters said they were against it, as did three-quarters of Canadians between the ages of 18 and 34. Not coincidentally, the NDP has proven popular with those younger voters, both in Quebec — where the party won 58 of 75 seats in 2011 — and in Alberta.

The days are gone of party loyalty, that people can't move - Lorne Bozinoff, Forum Research Trudeau indicated in March that his position on Bill C-51 was meant to counter potential Tory claims about his stance on terrorism, and said he would amend parts of the law should the Liberals win power. According to a Huffington Post report, Trudeau told UBC students that he hoped the Conservative government, "realizes from public pressure that it is going to have to make significant amendments to this bill. But we know that, tactically, this government would be perfectly happy if the opposition completely voted against this bill because it fits into their fear narrative and [their desire to] … bash people on security." "I do not want this government making political hay out of an issue … or trying to, out of an issue as important as security for Canadians," Trudeau added. "This conversation might be different if we weren't months from an election campaign, but we are." On Wednesday, the Liberal party joined the Conservatives to pass the bill by a margin of 183 to 96, with the NDP and Green Party opposing.

"There could be some migration from the Liberals to the NDP with this," says Lorne Bozinoff, president of Forum Research. "The days are gone of party loyalty, that people can't move."

Despite that, political pundits warn against giving the C-51 anger or Alberta results too much weight in the upcoming federal election, expected in October. Some say the opposition is coming mostly from individuals and groups that wouldn't vote Conservative anyway, and that the legislation doesn't matter to the general public.

'The Alberta effect'

"If we don't have any [events] between now and then that are traumatic, this bill won't feature in the election," says Nelson Wiseman, director of the Canadian studies program at the University of Toronto. "There's something to it today, tomorrow, the next day. Two, three months from now, the Alberta effect won't be there as much."

Alberta NDP Leader Rachel Notley heads to the stage to celebrate her majority victory in the provincial election on May 5, 2015. (Mike Ridewood/Canadian Press) Jim Lightbody, chair of the department of political science at the University of Alberta, says the NDP's provincial win was a "home-grown populist revolt" that won't necessarily translate into change on a federal level. Albertans, he says, are sophisticated voters who are able to treat federal and provincial matters differently.

"If the vote were held today, we have 34 seats and 33 of them would go Conservative," he says.

If the provincial election holds any lessons for the federal parties in the rest of Canada, he adds, it's that they need to listen to what voters are saying, which outgoing Premier Jim Prentice failed to do. He thinks the Harper government, which resisted making substantial modifications to C-51 despite widespread requests to do so, could find itself in a similar situation.

"If a government doesn't listen and is widely perceived to be untrustworthy, they're going to have trouble," Lightbody says. Bill C-51 is "a trigger or an explanation for why we don't like Conservatives."