What If the NDP Replaces the Liberals?

Here's a question: what would happen if the NDP "replaces" the Liberals in the popular vote? I will look at two interpretations of this question:

1. The NDP gets to 26.3%, the Liberal vote share in 2008
The Dippers are at 21.2% right now in my polling average. I therefore increase their vote share by 5.1% throughout the country, drawing from the other parties as follows:
- Atlantic and Ontario: 3.5% from Liberals and 1.5% from Tories
- Québec: 3% from Bloc, 1.5% from Liberals and 0.5% from Tories
- West: 2.5% from Liberals and Tories
I'll assume the other 0.1% comes from the Greens.

The resulting popular vote would be roughly: 36.8 C, 26.3 N, 23.4 L, 7.2 B, 5.1 G.

North: 2 N, 1 L
BC: 20 C, 12 N, 4 L
AB: 27 C, 1 N
SK: 12 C, 1 N, 1 L
MB: 9 C, 4 N, 1 L
ON: 56 C, 31 L, 19 N
QC: 36 B, 14 N, 12 L, 12 C, 1 I
NB: 7 C, 2 L, 1 N
NS: 5 L, 4 C, 2 N
PE: 3 L, 1 C
NL: 4 L, 2 N, 1 C

Canada: 149 C, 64 L, 58 N, 36 B, 1 I

In this scenario, the Conservatives are virtually unaffected, while the NDP, unsurprisingly, draws from the Liberals and the Bloc. It would be a tossup as to who forms the Official Opposition, though the model gives the edge to the Grits. The Bloc still wins the Québec seat count by a large margin despite losing the popular vote by 2-3%. However, it would be the first time since its creation that it fails to win a majority of seats in La Belle Province.

If the Liberals hang on to the second most seats, this might not be a realignment election provided that their new leader is a bit more adept than Dion or Ignatieff. The Conservatives would almost certainly govern as a minority. Even if the NDP comes in second, it would likely not been legitimized to govern with around 60 seats.

2. The NDP leads the Liberals by 8.1%, the same as the Liberal-NDP gap in 2008
Here, I will consider an 8.5% NDP gain throughout the country, drawing from others as above, but scaled up by two thirds.

The resulting popular vote would be: 36 C, 29.7 N, 21.6 L, 6.7 B, 5 G. Note that the Conservative-NDP gap would be similar to the Conservative-Liberal gap in 2006.

North: 2 N, 1 L
BC: 18 C, 15 N, 3 L
AB: 27 C, 1 N
SK: 11 C, 2 N, 1 L
MB: 9 C, 4 N, 1 L
ON: 59 C, 27 L, 20 N
QC: 33 N, 23 B, 11 C, 7 L, 1 I
NB: 7 C, 2 L, 1 N
NS: 5 N, 3 L, 3 C
PE: 3 L, 1 C
NL: 4 L, 2 N, 1 C

Canada: 147 C, 85 N, 52 L, 23 B, 1 I

Once again, on the net, the Tories shrug. They get a much more comfortable minority than with a similar vote margin in 2006. Those 3.4 extra percentage points really pay off for the NDP, who get 27 more seats! Fully 19 of these are from Québec, where the NDP really lays into the Bloc by carrying the province by 8%. The Liberals are left with a grand total of 7 seats west of the GTA.

In this case, it's harder to tell what would happen. With 85 seats and nearly 30% of the vote, the NDP might feel comfortable trying to form government. This would present the Grits and Bloc with a very hard choice: prop up Harper and risk further alienating left-of-centre voters, or accept that Jack Layton becomes Prime Minister, which might relegate them to oblivion. Both the Liberals and Bloc would probably like to vote against Harper, and yet have a Conservative minority so that Layton does not become PM. This would get very very interesting!