Let's hope this is just rhetoric.
Because it's a massive step towards 'one world government.'
The globalist desire is for bigger and bigger combinations that are ultimately merged into one someday. 
Discussion
I don't know why he's still on this. Assuming theres no shenanigans or arranged outcomes when it comes to elections, and we're taking everything on its face, wouldn't bringing Canada into the mix mean that he and his allies will never get electoral wins ever again?
*at a national level
I like the idea of absorbing Canada but in reality we would only want Alberta, the rest of that place is filled with purple haired crazies.