It will be interesting to see what degree of granularity they go for, some auto parts apparently cross the border up to 8 times. 

How will a component that is imported from Taiwan, put into an assembly in the US, then exported to Canada for an other assemble that is put into a final product in Ohio, which is then sold back to Canada count? How do you allocate the value added?

You will probably see the trade deficit with China shrink, but with other Asian countries expand - that $750 iPhone imported from China that is currently recorded as a $750 Chinese import will suddenly become $50 China, $100 Taiwan, $100 Japan, $50 UK, $50 Holland, $400 US