Andrei Zvyagintsev’s Leviathan has been called the most important Russian film in decades. A scathing indictment of the corruption and cruelty of the current Russian political regime. A window into the Russian soul. So, naturally, it was inspired by a muffler repairman in Colorado. Zvyagintsev — who made The Return, which became an international art-house hit after winning 2003’s Golden Lion at the Venice Film Festival — says the idea for Leviathan first came to him after hearing the story of tabloid hero Marvin John Heemeyer, a 52-year-old auto shop owner in Granby, Colo., who turned his tractor into a homemade tank