LOS ANGELES (AP) — Many of the winners who will take home an Oscar on Sunday have long been forecast, their triumph made seemingly self-evident after months of anticipation. That is, except for one little category: Best picture.

Even in a particularly lengthy awards season (the Academy Awards were pushed back slightly for the Olympics), and despite the tireless analysis of an ever-swelling Oscar blogosphere, no one really knows which film is going to take the night’s biggest award.

This Oscars, more than any in years, will go down to the wire.

Of the nine best picture nominees, the front-runners are widely considered to be Alfonso Cuaron’s 3-D spectacle ‘Gravity’, Steve McQueen’s historical odyssey ’12 Years a Slave’ and David O Russell’s corruption comedy ‘American Hustle’.

The industry guild awards, usually the most predictive honours, have only muddied the waters.

Actors, the largest branch of the Academy of Motion Pictures, have been most enthusiastic for ‘Hustle’.The Screen Actors Guild awarded it their top honour. Just as Russell’s ‘Silver Linings Playbook’ did last year, ‘American Hustle’ managed the very rare feat of landing nominations in all four acting categories (for Christian Bale, Amy Adams, Jennifer Lawrence and Bradley Cooper).

Cuaron and ‘Gravity’ won at the Directors Guild. The Producers Guild couldn’t even decide: ’12 Years a Slave’ and ‘Gravity’ tied for its top prize. ’12 Years a Slave’ also won best picture at the Golden Globes and at Britain’s BAFTA Awards.

Is history any guide? Last year, the academy was also faced with a choice between an historical epic centred on slavery (‘Lincoln’) and a 1970s caper (‘Argo’) and it went for Ben Affleck’s more ebullient option. ‘American Hustle’ shares a lot with ‘Argo’, including its wardrobe.

But this year, the weight of ’12 Years a Slave’ is suspected to be impossible to deny. The ‘Gurus o’ Gold’ poll of Oscar onlookers by film blog Movie City News has nine of 15 analysts predicting McQueen’s drama. The others chose ‘Gravity’, which all agree will clean up in technical categories like visual effects and cinematography.

Awards for either film (both of which premiered in September at the Telluride Film Festival within days of each other) could mean Oscar history. If the Mexican filmmaker Cuaron takes best director, as he’s expected to, he’ll be the first Latino winner in the category.

Similarly, were the British McQueen to win best director, he’d be the first black filmmaker to win. And if ’12 Years a Slave’ wins best picture, it will be the first time a film directed by a black filmmaker wins the academy’s top honour.

Such landmarks of diversity would be welcome for the academy, whose approximately 6,000 members are overwhelmingly older white men. A 2012 study by The Los Angeles Times found that Oscar voters are almost 94 per cent white and 77 per cent male. African Americans, the Times found, make up about 2 per cent of the academy, and Latinos are less than 2 per cent. Voters (who keep membership for life) have a median age of 62.

The academy is trying to change that, and has recently opened up its ranks to hundreds of new members. Sunday’s ceremony will be the first for new president, Cheryl Boone Isaacs, the academy’s first black president.

So as the make-up of the academy gradually shifts, the awards it picks could, too. This year’s best picture race offers stark choices between your big box-office crowd-pleaser (‘Gravity’), your hard-to-watch history lesson (’12 Years’) and your actors-having-a-ball party (‘American Hustle’).

Whichever film wins will crown not just a razor-thin race (Harvey Weinstein has called it “the most competitive season I’ve ever seen”), but a particularly strong best-picture field in a year roundly hailed as an excellent one for movies.

Also nominated is Spike Jonze’s futuristic romance ‘Her’, Alexander Payne’s black-and-white road trip ‘Nebraska’, Martin Scorsese’s financial meltdown ‘The Wolf of Wall Street’, the Texas AIDS drama ‘Dallas Buyers Club’ and the family history investigation ‘Philomena’.

It’s only fitting that a movie year so full of drama should end as a nail-biter.