Firstly it gives Poilievre an honest opportunity to contribute. People want to see everyone working together, so by letting Poilievre in right away he’s giving him a chance to temper the rhetoric and get work done. And if he doesn’t temper the rhetoric, it’s likely to work in Carney’s favour. If he’s seen as obstructing, it will not look good for him. It seems like a win-win-win… It looks like fair dealing, if Poilievre comes to the table honestly it works for Carney, if he doesn’t it works for Carney as well. It’s good politics that is both strategic in the way it encourages good cooperation and has good optics around fairness.
Secondly, the elephant in the room is the separation nonsense. Poilievre is running for a seat in the heart of separatist country, and with the separation rhetoric ramping up, better to have Poilievre - who is ideologically tied to Smith and will be representing Alberta - in the public eye as soon as possible, so he can wear this garbage. After all, Smith seems to be adept at causing no end of hassle for Poilievre. Best to put him front and centre as soon as possible so he is forced to respond to it.
I don’t think this is Carney’s intent at all. I think this is done fully expecting PP to be just as petulant as he’s been all this time. It’s to show that he’s just as terrible as everybody who voted against him knows him to be, and to make his supporters start to really think about who they voted for. Not to mention that PP will accomplish absolutely nothing as the official opposition leader, since Carney only needs three seats to vote for anything, and he can get that from the NDP that’s most closely aligned to the Liberals, or even the Bloc that have openly stated to form a ceasefire as long as Trump continues to attack Canada.
It’s far better than risking the Conservatives getting an actually competent leader that can rally their constituency when they’re already looking like they’re breaking at the seams. By allowing PP to have a seat and be official opposition leader, it makes it harder for the Conservatives to remove PP and put someone else in, which puts further strain on their cohesion.
I feel like Carney’s move is an attempt to make the Conservatives break apart with the realization that this election was the best chance they had at gaining power in a long time, and things will look worse because it’s almost impossible for Carney to screw up in ways that’ll make his support weaker the next election as long as he continues to play hardball against Trump.
At the very worst, he can treat the guy like a mild annoyance, since no matter how loudly he yells, it’s easy to ignore him when the Conservative vote means nothing in this virtual majority government.