In the infamous 1981 case of Oscar campaigning gone awry, Paramount pushed Susan Sarandon for supporting actress in “Atlantic City” but voters ignored the ads and served up a surprise nod for actress instead. Even the surprised Sarandon admitted she had voted for herself in a supporting role.Every year the game of trying to manipulate voters and blur the line between what is lead and what is a supporting role escalates. Timothy Hutton (“Ordinary People”) and Tatum O’Neal (“Paper Moon”), to name just two, have supporting Oscars for what are unquestionably leading roles. The Academy rules state it is up to the voters to decide in which category to nominate an actor or actress but that doesn’t stop studios from trying to twist a few arms. This year Focus Features is pushing Jake Gyllenhaal, Heath Ledger’s co-star in “Brokeback Mountain,” for supporting. The thinking is that this will separate him from Ledger’s Oscar lead actor heat and allows Gyllenhaal not to compete against himself for his lead turn in Sam Mendes’ “Jarhead.” Many also thought Diane Keaton would be campaigned in the lead actress category for her central role in “The Family Stone,” but Fox has other plans. “I think Diane is a classic supporting character in the sense that she really does support all of the other characters,” says Fox co-chair Tom Rothman, putting his spin on the strategy. “You could make an argument the other way because everything revolves around her as the mother, but it’s such an ensemble piece she thinks it’s supporting.” Often these decisions are simply made because studios and thesps see better opportunities in the supporting categories, not only for a nomination but a win as well. A major star such as Keaton or an actor with a large role like Gyllenhaal can have an advantage being nominated in the supporting categories. This year’s potential supporting actor list includes veterans such as Geoffrey Rush in “Munich,” Bob Hoskins in “Mrs. Henderson Presents,” William Hurt and Ed Harris in “A History of Violence,” Richard Jenkins in “North Country” and, in the sentimental slot, the never-nominated Donald Sutherland in “Pride & Prejudice.” Others possibilities include Clifton Collins, Jr. as Perry Smith in “Capote,” Peter Sarsgaard and Jamie Foxx in “Jarhead” and “Cinderella Man’s” Paul Giamatti, who many think has been overlooked twice, for “Sideways” and “American Splendor.” “Anyone who is a card-carrying member of the Academy who doesn’t remember Paul Giamatti’s great work should be drummed out of the organization,” says Maltin. For supporting actress, in addition to Keaton, there’s Oscar-winning vet Shirley MacLaine going against type in “In Her Shoes” and Frances McDormand, who has a couple of meaty scenes in “North Country,” as well as Brenda Blethyn as feisty Mrs. Bennett in “Pride & Prejudice” and Uma Thurman for her scene-stealing turn in “The Producers.” The rest of the list could be filled out with Oscar newbies Michelle Williams of “Brokeback Mountain,” Scarlett Johansson in “Match Point,” Gong Li and Michelle Yeoh in “Memoirs of a Geisha,” Maria Bello in “A History of Violence,” Catherine Keener as Harper Lee in “Capote” and Rachel Weisz in “The Constant Gardener.” Then there’s the “Crash” committee. Clearly a frontrunner for SAG’s cast award, the May release could also capture Academy attention for supporting actors Don Cheadle, Terrence Howard and Matt Dillon as well as supporting actresses Sandra Bullock and Thandie Newton. “We’re supporting all of our ‘Crash’ actors equally but those that make the greatest effort getting out there on their own and keeping themselves visible will have the best shot at separating themselves from the pack,” says Lions Gate president Tom Ortenberg.