Tariffs on Mexico would be especially tough on Arizona, which imported $9 billion worth of goods from its southern neighbor last year, nearly three times as much as from its next closest trading partner, China. The historically Republican state voted narrowly for Trump in 2016, but in last year's midterm elections Democrats picked up offices they had not won in decades. Arizona is expected to be a battleground in the 2020 presidential election and will have a crucial Senate contest.