Whenever an actress takes on a gritty working-class role, the audience does a gut check of authenticity. Either the actress gets it, like Melissa Leo did in Frozen River, or she doesn't, like Michelle Monaghan as the spoilin'-for-a-fight truck-driver heroine of the inert indie dud Trucker .Monaghan, so good in Gone Baby Gone, mopes self-consciously through the role of Diane, a loner who finds her heart when she's thrown together with her estranged 11-year-old son (Jimmy Bennett), whom she takes on the road. Yes, it's one of those movies.
