Tourists from Chattanooga check into beach resorts in Cancun. Canadian auto parts feed factories in the American Midwest – and vice versa. Happy Hour revelers raise glasses of Mexican tequila and mezcal at bars in Seattle.

It adds up. The United States trades $1.9 trillion a year -- $5 billion a day – worth of goods and services with its neighbors, Canada and Mexico. They have supplanted China as America's top two trading partners.