Polls are suggesting the federal election race is close and could go down to the wire. But the campaign still has more than two months to go, and some voters — perhaps many or even most — could change their minds between now and election day.

So who has the most committed supporters, and who is at risk of losing waverers to one of their rivals?

The votes of many Canadians remain up for grabs. Apart from the 15 to 20 per cent who say they are still undecided in most surveys, fully 60 per cent told Nanos Research in a recent survey that they are considering their options. Only 40 per cent had said that they had already made up their minds. This aligns with a survey conducted by Abacus Data in early July that showed 36 per cent of Canadians would only consider voting for either the Conservatives, Liberals or NDP.

Of those who have already settled on their choice, the polls suggest the Conservatives have the most dedicated voters. When respondents were asked whether they were "a strong supporter" of their preferred party in a recent poll, 70 per cent of Conservative voters told Forum Research that they were. That compared to 60 per cent among Liberals and 56 per cent among NDP supporters.

Second choice polling, particularly in terms of those who say they have no second choice, is also quite revealing. In its most recent poll, EKOS Research found that 59 per cent of Conservatives could not name a party they would consider their second choice. Only 33 per cent of New Democrats and 35 per cent of Liberals said the same thing.

Green voters seem the most willing to consider other options, with just 26 per cent saying they had no second choice. With about half not naming another party, Bloc Québécois supporters were the most committed after those of the Tories.

Options to the left of Harper, none to the right

With Conservative voters believing their choices limited, it is to the left of Stephen Harper that voters see more options. But neither the Liberals nor the New Democrats seem to have the clear advantage, suggesting that whoever is seen as the best alternative to the Conservatives may take the lion's share of those voters seeking change.

NDP Leader Tom Mulcair, greeting supporters in Hamilton last month, currently has the highest ceiling of the main party leaders when it comes to picking up potential swing voters, recent polls suggest. (Samantha Craggs/CBC)

If the Conservatives do lose some of their waverers, it is not entirely clear where they would go. In the EKOS survey, 14 per cent of Conservative voters said their second choice was the NDP, little different from the 13 per cent who instead chose the Liberals. However, Conservatives are far more likely to approve of NDP Leader Thomas Mulcair than they are of Liberal Leader Justin Trudeau. If the Tories drop in the polls in the coming weeks, then, the NDP may stand to benefit most.

Among New Democrats, the Liberals are the consensus second choice. In the EKOS poll, 34 per cent chose the Liberals, more than twice as often as any of the other parties. And between 40 and 41 per cent of New Democrats, depending on the poll, approve of Trudeau.

The Liberals may be in greater danger, however, of losing waverers to the NDP. While 11 per cent of Liberal supporters said the Tories were their second choice, 43 per cent chose the NDP instead. And though the recent Forum poll showed about as many Liberals approving of Mulcair as New Democrats approved of Trudeau, EKOS found Mulcair's approval rating to stand at 57 per cent among Liberal voters.

If the NDP does have a more obvious advantage over the Liberals, it may be among Green and Bloc voters. Greens are twice as likely to choose the NDP as their second choice as they are the Liberals. Bloc voters are more equivocal on second choice, but Mulcair's approval ratings among this group are far superior to Trudeau's. If supporters of these parties decide they should instead throw in their lot with a party more likely to form government, the NDP is in the best position to take those votes.

However, these calculations may change if the NDP and Liberals swap position in the polls. Voters may already be baking in the relative standings of the parties into their responses.

Majority government numbers accessible to all parties

These shifts between parties may come at the margins, moving just a few percentage points' worth of support one way or another. But all three leaders need to make major gains in order to approach the threshold for a majority government. The polls suggest all three parties do have the accessible voters to do it — but the NDP's ceiling is the highest.

Polling by Nanos found that 50 per cent of Canadians would consider voting for the NDP, while the Abacus July poll pegged that number at 62 per cent. This was the highest score for any party in both polls, with the Liberals registering between 45 and 55 per cent, respectively, and the Conservatives between 42 and 45 per cent. More than enough for a majority government.

But this gives the NDP the largest margin for manoeuvring, and most of that will have to take place on the left of the political spectrum. The Abacus Data poll showed that 23 per cent of Canadians were Liberal-NDP swing voters, by far the largest group. Only 9 per cent said they were Conservative-NDP voters. Most intriguingly, however, 15 per cent said they could cast a ballot for all three major parties.

In an election where five or six points separates all three parties in voting intentions, this swing group, in addition to the large number of uncommitted voters, has the potential to send the direction of the campaign careening any which way.

Full methodological information, including links to the original surveys, can be found at the CBC Poll Tracker.

The questions asked in the polls cited in this article were as follows:

Nanos: "For each of the following federal political parties, please tell me if you would consider or not consider voting for it."

Forum: "Are you a strong supporter of that party?" and "Do you approve or disapprove of the job [leader name] is doing as [role]?

EKOS: "If a federal election were held tomorrow, which party would you vote for? Which party would be your second choice?" and "Do you approve or disapprove of the way [leader name, role] is handling his/her job?

Abacus: "Would you consider or not consider voting for the following federal political parties?"