Leading vs. Supporting Categories in 2011 …
IMO Berenice Bejo was the leading actress in The Artist. Oscar had her in the supporting category. She may have had a lesser role than Jean Dujardin but I didn’t feel she was supporting any other actress and her part was sufficiently large to be considered a lead.
Jodie Foster, Kate Winslet, John C. Reilly and Christoph Waltz are all leading actors in Carnage.
George Clooney is supporting in The Ides of March.
Shailene Woodley is supporting in The Descendants.