Apparently E15 year-round was a campaign promise. I don't recall it specifically but he made a lot of them so it's hard to keep track.
It isn't just trade where it'll be made up. It'll also be made up by simply fewer illegal Mexicans in the country sucking us dry. They've been fucking us over by taking money completely out of our economy. They remit it home, probably no taxes paid on it, and it leaves our economy. Probably forever. No taxes paid. It's like a black hole.
Goddamn obscene amount of money sent back there every year. Ran a quick check and it was ~$25.2B from US to Mexico back in 2015.