***Powerful message in a melancholic drama bogged down by un-real contrivances and other issues*** A father and son (Billy Bob Thornton and Heath Ledger) are correctional officers in Louisiana who live with their father, a former corrections officer and hateful racist (Peter Boyle). After overseeing the execution of a black man (Sean 'Diddy' Combs) a couple of tragedies compel the father, Hank (Thornton), to meet the struggling ex-wife of the executed man (Halle Berry). The cast, locations, score and directing are all excellent. The problem is the contrived script, which tends to focus on…