I don't understand what you're arguing. In the Westminster System generally, and the Canadian variant specifically, the leader of the party holds immense power.

I don't understand what you're arguing. In the Westminster System generally, and the Canadian variant specifically, the leader of the party holds immense power. Obviously there is no legal requirement for MPs to vote a certain way, but in practice the party leader, and the whip will force votes it deems important from party members . And yes, getting kicked out of the party or losing cabinet or committee assignments is normal punishment for insubordination. The end result is that MPs are much more disciplined around voting along party lines than, for example, House members are under the American system. In fact, the American Congress is a wild-west compared to the strict discipline you find in the Canadian Parliamentary system. You would never see a Joe Manchin-type of behaviour when a party member breaks ranks to vote against a candidate pushed by the party leader (or whatever the equivalent would be in the Canadian system). That never happens. I suspect that Trudeau in this case wanted to have his cake and eat it to. He allowed a free vote for Liberal MPs while he and leadership abstained. This way he isn't on record one way or the other and therefore limits how pissed China would be, and at the same time limit the amount of criticism he would get from opposition had he forced a particular vote on his MPs.