Drain the Atlantic ocean?

Load Canada onto a barge and move right next to the EU?

Geography is always going to be the number one factor in this.

Develop shipping infrastructure east of Montreal as well as expanding the railway (both cargo and passenger).

We really only have Halifax as an east coast shipping hub. There is only so much capacity available here as well. We need another port with rail access.

Arrest people and/or nationalize companies that take American capital.

Melt the NW passage? Then we’re next to the freeway anyway.

We can't. One geography and two Americas economy is massive you can't replace it.