With less than three months to go until Election Day, Premier Christy Clark's Liberals are betting on a major come-from-behind surge to wipe out the New Democratic Party's lead in the polls.

It's a tall order, but it wouldn't be the first time voters have shifted that much, that fast.

"Things can change very quickly," said Angus Reid pollster Mario Canseco. Even when an opposition party enters an election campaign with a healthy lead, voters can abandon it if they decide the party isn't ready to govern.

For the past several years, the NDP has held a robust lead over the BC Liberals in the polls. Although the lead has dropped from highs of 20 points or more, the most recent polls still show the NDP up by 10 to 15 percentage points.

But headlines like Hudak Tories Roaring Toward a Majority: Poll and Danielle Smith's Wildrose on Track for Majority suggest just how volatile voters can be. And headlines like 'We Were Wrong': Alberta Election Pollsters Red-faced as Tories Crush Wildrose serve as a reminder that polls are a snapshot in time, not a forecast.

Some experts believe that polls taken months ahead of Election Day should be taken with several grains of salt. They believe the people pollsters talk to between elections just aren't paying attention.

Time bends polls

André Turcotte, a professor at Carleton University who has worked for the Gallup Poll and polled for the federal Liberal Party and the Reform Party, argues that polls tend to be more accurate near the end of a campaign.

"Polls published between elections reflect the voting intentions of a largely fictitious electorate, too disinterested and disengaged to reflect seriously about which political party would be likely to get their support," Turcotte writes in The Canadian Federal Election of 2011.

Turcotte adds: "Only when people are engaged in the election do horse-race numbers actually reflect the mood of the voting public."

Pollsters respond that they ask how people would vote if an election were held today. As we'll see, the answer may be different tomorrow. Here are some campaigns that defied the early polls:

Comeback #1: B.C. -- May 1996

You have to go almost two decades to find the last time someone blew a really big lead in this province. In November 1995, the governing NDP trailed the Opposition Liberals by 25 to 30 points in the wake of a damning report into the Bingogate scandal.

Then premier Mike Harcourt resigned.

After an energetic leadership campaign, the NDP chose Glen Clark as his successor. Suddenly, the NDP found themselves within striking distance of Gordon Campbell's Liberals.

Clark began the election campaign in February, the day he was sworn in as premier. With Clark's leadership, "we just ran a full-bore campaign," recalls Bill Tieleman, who was Clark's communications director. "We froze tuition rates, froze ICBC rates, froze ferry rates, increased the minimum wage.

"There was at least one announcement on every working day if not every calendar day of things that the government was doing.... It was a relentless public relations exercise by the new government."

All that activity still wasn't enough to pull the NDP ahead of Campbell's Liberals in the popular vote, but it was enough to win. On election day, the NDP pulled in 39.5 per cent of the vote, compared to the Liberals' 41.8. But, because of the way the two parties' support was distributed, the NDP took 39 seats to the Liberals' 33.

A squeaker, true, but a lot closer than the 30-point spread the Liberals had once enjoyed.

Comeback #2: Alberta -- April 2012

If you don't believe large chunks of the electorate can shift almost overnight, just ask Danielle Smith, leader of Alberta's Wildrose Party. Election polls showed Smith on track to be premier through most of the campaign. On election night, pundits were confidently predicting the province would swing to the right.

Instead, Premier Alison Redford's Progressive Conservatives were re-elected with a 10-point margin.

This goes to show you can't trust polls, Christy Clark has said. But pollsters and Wildrose say there was a big shift in public opinion in the last days of the campaign. Wildrose insider Vitor Marciano called the stampede away from his party "breathtaking, with 12-point swings in some places."

Said Marciano: "I can't think of a swing that size in the last 48 hours in any other Canadian or American election. I think it was unprecedented."

A clue to what happened can be found in a Leger Marketing poll commissioned by the Edmonton Journal and Calgary Herald. The poll, taken over a three-day period ending one week before election day, suggested Wildrose held a six-point lead over the Tories among decided voters. But there were plenty of people who hadn't made up their minds, the poll suggested -- 20 per cent of all respondents. And they were leaning toward Redford's PCs by a six-point margin.

Leger vice-president Ian Large cautioned that "a six-point lead for Wildrose may be hard for the PCs to overcome on Monday, but with one in five still undecided, the final week of campaigning will be critical for all parties."

It was. With a week to go in the campaign, Smith refused to condemn a Wildrose candidate's online musings on the Lady Gaga song Born This Way.

Candidate and evangelical pastor Allan Hunsperger had this advice for gays: "You can live the way you were born, and if you die the way you were born, then you will suffer the rest of eternity in the lake of fire, Hell, a place of eternal suffering."

At around the same time, another Wildrose candidate told a multicultural radio station that, unlike Sikh or Muslim community leaders, he "can speak to all the community" because he is white. Comments like that seem to have driven voters, including Liberal supporters scared of a Wildrose win, to Redford's Tories. Wildrose was, to a large extent, an unknown entity even near the end of the campaign and many Alberta voters decided they didn't like what they saw.

Moderate voters expected Smith to repudiate these intemperate comments, said Canseco. When she didn't, they decided Wildrose wasn't ready to govern.

Comeback #3: Ontario -- October 2011

Just over three months before election day, a Forum Research poll put Tim Hudak's Progressive Conservatives 15 points ahead of Dalton McGuinty's incumbent Liberals. A month before that, Nanos Research had the Hudak's Tories up by seven points.

But on election night, McGuinty came out on top, taking 37.7 per cent of the vote compared to Hudak's 35.4 per cent -- enough to form a minority government.

How did Hudak blow it? Some feel he ran a poor campaign that focused on what one pundit called "phony issues."

"He and his candidates spent way too much time talking about how he would put prisoners to work and put global positioning systems on sex offenders," wrote columnist Luisa D'Amato. "And attacking Liberals for their plan to help a small number of recent immigrants find jobs."

Hudak had been hammering McGuinty with ads that labelled the premier as "The Tax Man." The attack may have helped create the Conservatives' early lead, but the Liberals fought back with their own negative ads, which may have helped turn the tide.

Again, once the voters of Ontario started to pay attention to Hudak and his party, it seems they weren't impressed by what they saw. Canseco said his polls suggest that fence-sitters moved away from Hudak in the final week of the campaign.

"People realized they weren't ready," he said.

Comeback #4: Manitoba -- October 2011

Just over six months before the election, Greg Selinger's NDP government was in trouble. A poll put it 12 points behind Hugh McFadyen's Progressive Conservatives. But when the votes were counted, Selinger rode a slim lead -- 46 per cent compared to the PCs' 43.9 per cent -- to a hefty majority in the legislature.

Selinger had closed the gap with the Tories during the late spring of 2011 and by June the two parties were neck and neck. Many pundits believe the NDP won that campaign on a combination of a positive economy and negative ads.

The NDP ran a series of ads built on the question "who is Hugh McFadyen?" that accused the Tory leader of having a secret agenda to privatize health care and Crown corporations. McFadyen was too risky to trust, the NDP argued.

Canseco isn't sure the negative ads were the key. He thinks Selinger picked up support during the Lake Manitoba floods that hit the province during the summer of 2011. The premier was on the scene, talking to people, expressing sympathy.

"He really came across as somebody who cared," Canseco said.

Some have suggest that Clark's Liberals will use Manitoba as the model for their campaign. But Canseco isn't sure that will work.

"She's not Selinger," he said.

He said Angus Reid's polling indicates that voters' opinions of Clark are based on conflicting images that change from day to day. With Clark, "for every person who says they dislike her because she's too casual, there is another person who dislikes her because she is too formal."

That suggests there is "no coherence" to the Liberal communications strategy, he said.

Which raises a question about whether history can repeat here. Come-from-behind wins tend to be built on effective campaigns. Can the Liberals mount one? So far, the Liberal bandwagon has looked more like a runaway clown car. And missteps like the HST boondoggle may mean that voters will be unwilling to listen to Clark's message even when they do pay attention.