Why not? It is often said that parties don't win elections, incumbents lose them. Certainly there was an element of that at play in 2015 where much of the dissatisfaction with the Conservatives was directed at Harper himself rather than the Cons record in office. Trudeau remains personally popular but has slipped in the polls and is also seen as something of a vapid poseur. He has reneged on on key promises and doubled down on spending as his economic policies fail to bear fruit. This is a target rich environment for both opposition parties, albeit for different reasons. If the Tories can contain the swivel-eyed loons on the far right they may well have the basis for digging in to JT's majority.