This story is the first in a series on what political strategists say each of the main political parties needs to do to win the election. Today, it's the NDP; tomorrow, it will be the Liberals; and the day after that, the Conservatives.

Tom Mulcair and the NDP went into the 2015 election campaign in an enviable position -- top of the polls and with momentum to boot.

But 11 weeks is an eternity in any political contest, and the epic length of this one has clearly not benefited the NDP, who are now polling third.

"The dominant story right now is the NDP is in serious trouble," says Claude Denis, a political science professor at the University of Ottawa.

The party, he says, has lost "a significant portion of its Quebec gains, as well as its general momentum across the country that was built at least in good part on the perception that they were strong in Quebec."

In an attempt to reverse the party's fortunes, strategists and polling experts say the New Democrats are likely to hit hard on issues such as the recently signed Trans-Pacific Partnership, try to turn the Conservatives' emphasis on the niqab to their advantage and continue to make the argument to fence-sitting progressive voters that they are the party best positioned to unseat Stephen Harper.

That said, Mulcair's task in this last week or so of campaigning is "herculean," says Elly Alboim, a political consultant and the lead strategist at Earnscliffe Strategy Group in Ottawa.

Reversing the 'Orange crash'

According to CBC's Poll Tracker, when the campaign started on Aug. 2, the NDP was polling at 33.2 per cent support nationally. And as of Oct. 7, they're at 24.3 per cent.

One of the reasons for that decline is that the party is perceived as being on the wrong side of the niqab debate in Quebec where both the Conservatives and Bloc Quebecois have been stoking nativist sentiment.

The question of whether a Muslim woman should be allowed to wear a veil that covers her face while taking the oath of citizenship has emerged as an unexpected campaign issue.

In office, the Conservatives attempted to forbid that circumstance, but a Federal Court judge overruled them and the Federal Court of Appeal upheld the decision.

Still, a poll commissioned by the government and conducted by Leger Marketing in the spring found that 93 percent of Quebecers agree with a ban on the niqab in this situation, and defending the religious freedom of Muslim women has been a risky proposition for the NDP, who took 59 of the province's 75 ridings in 2011.

Eric Grenier, founder of the Canadian polling data site ThreeHundredEight, says Mulcair "can't change his position," but he and the party will likely try to change the conversation in order to salvage support in Quebec.

Mulcair has been trying to do that in recent days by suggesting that the niqab ban is part of the Conservatives' attempt to sow racial division and divert attention from the government's record on the economy.

Mulcair "has to convince Quebecers that [the niqab] is not the issue, the issue is defeating the Conservatives," says Grenier. He has to convince them that he is the one who can do that and provide the kind of government that they want.

As Grenier sees it, only if the NDP can correct its course in Quebec will it regain the momentum it needs to come out ahead on Oct. 19.

What's the strategy on strategic voting?

Another problem the NDP faces is that one of the main themes of the campaign is that there are a large number of left and centre-left voters who are so unhappy with the current government that they are willing to swap their vote for the candidate best positioned to unseat Harper.

"The number of people who say they are willing to consider switching their vote at the moment is probably at a historic high, and it's clustered largely among NDP and Liberal voters," says Alboim.

At the beginning of the campaign, with the polls behind him, Mulcair was the "default change agent," says Alboim.

But with the Liberals rising in the polls, many strategic voters are beginning to feel that Mulcair no longer represents the best chance for change.

No doubt sensing this, the NDP have been making the mathematical argument that if they add 30 or so new seats to the 103 they won in 2011, they are best positioned to defeat Harper, says Alice Funke, publisher of PunditsGuide.ca, a site that analyzes data on ridings.

But that argument is based on two assumptions: that the party will hold the seats it won last time, and that it can wrest more from the Liberals, who have been on the rise in Ontario in particular.

The University of Ottawa's Denis says that the NDP has run a competent if overly safe campaign thus far, but the party needs to be bolder to distinguish itself from the Liberals.

He thinks Mulcair may have found that issue with the Trans-Pacific Partnership, the wide-ranging free trade deal that is said to open Canadian markets to foreign products and vice-versa.

Exploiting divisions on TPP

The Conservatives have argued that the deal is a winner for the Canadian economy. The Liberals have criticized the lack of transparency in the negotiations, but have not really taken issue with the substance of the deal, most of which is still unknown.

The NDP, however, has heavily criticized it, saying the concessions on auto parts and the dairy industry will cost tens of thousands of Canadian jobs.

"The reason that [Mulcair] has seized on the TPP with such alacrity is because it's literally the only wedge issue he has with Trudeau that has any meaning," says Alboim.

He feels the NDP's attack on the TPP is likely to play well in ridings with agricultural and manufacturing centres and heavy union support.

This would include Quebec, where the dairy industry is entrenched, as well as the Windsor area, parts of the rural Prairies and B.C., where there is a higher base vote for the NDP than the Liberals.

Alboim says that to turn the issue to its advantage, the NDP is going to have "to work, particularly with union support, to identify enough ridings in enough places where they're No. 2 to cash in — plus try to build a bit on the anti-trade movement in the country."