Whit Stillman doesn’t want to talk about politics. Ask the famed indie film director for his thoughts about the current Republican primary race, and he politely — but flatly — declines. “No, I have nothing,” he says. Lightly pressed further, he changes the subject, turning the tables to ask questions of his own. [....] Mr. Stillman recalls directing an episode of the TV show “Homicide: Life on the Street.” He had a script he liked, but a rewrite turned a yuppie victim — whose family had been murdered — into “this awful, caricatured yuppie villain.” “We don’t necessarily want to...