“You watch her on the witness stand. You listen to her story. You note the righteous ferocity with which the prosecution defends that story. You note the timidity with which the defense challenges it. You count the dead . . . Ernest Thomas . . . Sammy Shepherd . . . maybe Walter Irvin . . . and you realize that it’s perfectly all right to starve a Southern white woman and deprive her of education and make her old before her time, but by God, no damned outsider is going to dare question the sanctity of her private parts, the incontrovertibility of her spoken word.”