No mere gimmick, David Mamet's genre shift from crime drama to costume drama is executed with the confidence and panache of a Merchant-Ivory standard-bearer. But The Winslow Boy also shares those films' sense of emotional retreat, and feels as though some key scenes were excised, weakening its narrative fluidity and arc toward a fulfilling climax. Mamet gets all the design details right, but something about the case itself -- how could there be this much public furor over five stolen shillings? -- never rings true. Yes, it's an indictment of the whole British sovereignty and its corresponding legal system, based on actual events, but it was Mamet's choice to include so many shouted headlines without the courtroom dramatics that would have convinced us of its galvanizing force. If a store window posting reads, "No discussing the Winslow case," Mamet should provide corresponding footage to give this sentiment weight. Mamet does expertly handle his chosen area of focus: the intimate parlor deliberations between family members and others involved in and/or affected by the case. Should they persist in a defiant campaign to vindicate young Ronnie, even as it dissolves their resources and erodes the very social standing the suit was designed to protect? Nigel Hawthorne and Jeremy Northam provide perfect locutions for Mamet's dialogue, but the overall effort is hampered by Rebecca Pidgeon, Mamet's wife, whose listless acting style is too amateurish for the increasingly important roles he's asking her to play. Mamet's nepotism extends even further than usual here, providing Rebecca's brother, Matthew Pidgeon, his first-ever screen role as Dickie, another child of the Winslow brood.