It’s not surprising that President Trump chose to be introduced at the Great American State Fair on the National Mall by country singer Lee Greenwood performing his signature song, “God Bless the USA.” Its lyrics, combining patriotism with combativeness, are perfect for Trump. “The flag still stands for freedom, and they can’t take that away.” “I’m proud to be an American, where at least I know I’m free.” Celebrations for the July 4 semiquinc…