The first sale of the Sundance Film Festival (which hasn’t even opened yet) is “Waiting for Superman,” the curiously-titled documentary by Davis Guggenheim that explores the teeming cesspool that is the US educational system. Paramount Vantage picked up worldwide rights to the film, which worked out pretty well for Par the last time they worked with Guggenheim, on “An Inconvenient Truth,” a film that merely won the Oscar and, for a couple of years, looked like it would lead to massive new levels of regulation of the US economy in an effort to curb carbon emissions, but even with Democrats controlling Washington, the climate-change bill is dead. Guggeneim’s last film, the music doc “It Might Get Loud,” had some wonderful moments in its effort to explore the common ground of guitarists Jimmy Page, the Edge and Jack White. I haven’t seen his education film but I am intriguted by one sentence in the program: “However, embracing the belief that good teachers make good schools, and ultimately questioning the role of unions in maintaining the status quo, Guggenheim offers hope by exploring innovative approaches taken by education reformers and charter schools that have — in reshaping the culture — refused to leave their students behind.” These arguments (emphasis mine) are the ones sensible observers of the education system have been making for 20 years or more, though rarely do liberals acknowledge the disastrous effects of teachers’ unions on inner-city school systems, and if Guggenheim can help move us toward a consensus around these ideas he is to be applauded.