Canada, America and Mexico should just form into one supranational state like the EU. Mexicans can be farm hands legally, like many Balkans come to Western Europe for seasonal farming, and the state gets development grants; American farms can get cheap labour without having to deal with headache inducing, Kafkaesque labour and immigration bureaucracy, ordinary Americans get free healthcare from Canada and American gun nuts could kill all the cartels they want. Meanwhile, Canada gets military protection from US and can holiday in sunny Cancun visa-free for Christmas.

Win-win!