"Selfishly, we need aluminum in this country. We don't have it. We get it all from Canada — for the most part — and we need it badly," 

right.

so, there is a high demand for aluminum in the us and a low supply. 

what would that mean in a market society (which i don't support, except right now, very sarcastically), which nafta has done more to break than enforce?

let's do what a capitalist supplier would do and increase the price of aluminum by slapping an export tax of...i dunno.....50%? on it.