Vote Splitting: How Mulcair And Trudeau May Be Handing Victory To Harper
Here is the list of the 28 ridings affected. There are technically 72 ridings where CPC is leading but NDP+LPC would be greater, but in most of them, the lead of the Conservative candidate would not be overcome by having a unique candidate (or coalition) between the other two (namely because not all NDP voters for instance would vote Liberals).
In these ridings, if the NDP and Liberals were to run a single candidate, they would likely win. 28 out of 338 isn't that much, but it does currently make the difference between Harper finishing first and third.
Too Close to Call