SOMETIMES IT takes a prominent visiting writer or artist — from de Tocqueville to, say, Bono — to serve up a storyteller’s view of the United States that is one shot of awed wonder and two shots of bracing honesty. Along that continuum of colorful outsider perspectives sits Ralph Steadman, that savage ink-slinging satirist from Kent who depicts the land of the free as a minefield of bullies and blowhards and presidents, not necessarily in that order and not without some redundancy.