For context I answered this question on Quora
Keeping his promise to be a belligerent moron on trade solely out of spite for our neighbors. He imagines that Canada and Mexico will bow down before his throne and concede to all of his whims.
Reality:he is the one that renegotiated the current USMCA which includes already established tariff schedules and tariff free importation of agricultural products between the 3 nations; a provision carried over from the prior NAFTA agreement. A 25% blanket tariff on goods from Mexico and Canada will provoke retaliatory tariffs, not submission, and everything on the shelves will get a whole lot more expensive especially dairy. An avian flu epidemic on our farms has already caused a shortage of eggs, poultry and dairy products. A trade war with our neighbors will only make prices for those things higher and make life a little worse for everyone in North America.