The first orange wave washed over Quebec in the last federal election. The second orange wave swept across Alberta in the recent provincial election. Can a third orange wave splash across Canada on election day, Oct. 19?

The short answer is no, if by wave we mean the kind of New Democratic Party sweep of Quebec federally and Alberta provincially. There are too many locked-up Conservative seats and some Liberal ones, too, for the federal NDP to do nationally what it and its provincial counterpart did in Quebec and Alberta.

But, occasionally, a tipping point arrives in politics that sees voters do things for the first time, with results that surprise even themselves. People can liberate themselves politically by voting as they never have before – or even voting for the first time. When that happens, a tide carries away incumbents previously thought unbeatable, as in Quebec and Alberta.

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Here's the case, about five months from voting day, for an NDP surprise.

The case starts with the apparent inability of the Harper Conservatives to expand greatly their base of support. The Conservatives have tried mightily – from a budget to foreign leaders' trips to ethnic outreach to massive advertising with taxpayers' dollars to almost full-time campaigning by Mr. Harper – but they don't seem able to climb close to the 40 per cent of the popular vote that would bring them another majority.

To date, opposition to the Conservatives hovers around 60 to 65 per cent of nominal voters. The Conservative base of 30 to 35 per cent nationally is solid, identifiable and easily motivated. But it hasn't grown much.

Maybe support will grow when the campaign begins, Conservative ads flood the airwaves and the leaders' debates occur, because Mr. Harper is, after all, the most experienced campaigner of the three main national leaders.

Stephen Harper himself and his party's partisan style enrage non-Conservatives. A lot of voters dislike the Harper Conservatives and will vote in a fury to rid the country of them. When voters passionately dislike someone, they will search for the best available means of change, assuming the alternative is marginally capable of walking and chewing gum at the same time.

NDP Leader Thomas Mulcair is more than capable of meeting the lowest tests of leadership. Maybe he's not a touchy-feely kind of guy, but then neither is the Prime Minister, who is a quite solitary figure, with few close friends and an aversion to being in a room with people he does not know.

Mr. Mulcair has held his caucus together with only a few quarrels. He's been a terrific questioner in the Commons as Leader of the Opposition, and he's a more than capable public speaker in both English and excellent French. Conservative attack ads depicting him as not ready for prime time or as some kind of menacing socialist will ring hollow.

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Conventional wisdom took hold some time ago that the Liberals with Justin Trudeau would be the anti-Harper vehicle of choice. So the Liberals might yet become, but at this point the Liberals' apparent inevitability as the obvious alternative to Mr. Harper has become at least questionable.

The Liberal platform offers a variation on Conservative policies, except notably for the Liberal plan to raise taxes on those earning $200,000 or more. Politically, the Liberals seem to be positioning themselves as the "safe" alternative to the Harper Conservatives.

The Liberals suggest that they will do some things differently – but not too many. They will be "nicer" in government than the Conservatives or, to use a frightful buzzword much favoured by the politically correct and linguistically challenged, more "inclusive."

If enough voters are really mad at the Conservatives and want to kick them hard, a vote for the Liberals' sort of soft, "inclusive" alternative might not provide the kind of satisfaction angry voters need. Then there is Mr. Trudeau himself, the question being: Will he wear well in the rough-and-tumble of sustained debate and constant media coverage?

A lot of voters want passionately to get rid of the Conservatives, but when they look at Mr. Trudeau they ask: Has he got what it takes? Mr. Mulcair's challenge is to get voters to look at him at all.

The failure of the Conservatives to grow and the Liberals' failure to seem like the inevitable alternative give the NDP a chance for a surprise.