Murray doesn't take straight comedic roles anymore, but he's a national treasure who still exudes a singular brand of melancholy nuttiness. In recent years he's made a habit of interacting with shocked strangers in public (like when he crashed a New York karaoke party), telling them "No one will ever believe you." Murray recently played FDR in Hyde Park on Hudson and promoted the film with a Letterman appearance in which he was wrestled in by stun-gun-wielding "kidnappers," smoothed down his suit, and announced, "It's nice to be back." What other actor could cameo as a (presumably) more stoned version of himself in Zombieland, then, three years later, take on a wartime president? Anybody else would just seem like a punchline.