Might it be to cut down on fentinal shipments? China is where most of it comes from, not that you would know that if you listen to Trump go on about Canada.
Unfortunately, the liberal party rules say they require a minimum of four months to elect a new leader. They may be able to fast track it in three months, but it’s entirely up to the liberal party so I suspect Trudeau will still be leader when Parliament resumes.
With Trudeau leaving, I suspect that at least one of the other parties will give them enough time to elect a new leader before bringing down the government. The government may even last until the required election date of late October however, nothing of any importance will likely be passed in that time