Directed by the recently departed Ivan Reitman (“Stripes,” “Meatballs,” “Twins,” “Kindergarten Cop”), “Dave” pulls off the rare feat of being rooted in politics without displaying any whiff of partisanship. Sophisticated but relatable and smart while coming off as erudite, it is a comedy with endless charm and an ability to impart a common sense message without standing on a soap box doing so. Writer Gary Ross received the movie’s sole Academy Award nomination (for Best Original Screenplay), something he also did a few years earlier with “Big” and later on down the road with “Seabiscuit.” Dave Kovic (Kevin Kline) is an amiable and affable man living in Baltimore where he owns a barely afloat employment agency. He has a side-hustle where he appears at retail grand openings and other events as a lookalike for current U.S. President Bill Mitchell (also Kline). The polar opposite of Dave in every way, Mitchell …