“Category fraud.” It's a phrase that means precisely nothing to anybody who doesn't scrutinize the Oscars with all the methodical dedication of a veteran trainspotter – but within that self-selecting circle, it's an issue that seems to prompt more heated opinions by the year.

Implying veritably criminal levels of bad faith, it's a strangely emphatic term for a practice that frequently occurs in the grayest of areas, amid such intangibles as narrative, perspective and character. The Oscar campaigning game has seen many dirty tricks and cynical strategies pass undetected over the years, but woe betide the supporting hopeful whose role is seen as a little too large for his targeted trophy, or the uppity ensemble player with ideas above his station – awards geeks do not easily forget such infractions.

Quite when the term “category fraud” was first coined, I don't know – but it was surely long after the question first surfaced at the Oscars. Indeed, the issue is as old as the supporting awards themselves, which were inaugurated in 1936 – one year after supporting star Franchot Tone's hopeless Best Actor nomination alongside his “Mutiny on the Bounty” co-stars Clark Gable and Charles Laughton prompted complaints that non-leads and character players weren't getting their due at an awards ceremony still in thrall to the star system.

That first year, Stuart Erwin, a top-billed but relatively unheralded star of a featherweight football comedy called “Pigskin Parade” spotted an opportunity, playing down his lead status to score a nod in the first ever Best Supporting Actor race. He didn't win, but he founded a not-so-proud Oscar tradition – one that could hardly be more alive and well in this year's awards race, where a range of actors, some more familiar than others, have pundits debating the merits (both ethically and strategically) of their campaign categorizations.

Take this morning's SAG nominations list as an example. The Best Supporting Actress category features two Oscar-winning stars in roles prominent enough to contend as leads: Helen Hunt, half of what often boils down to an intimate two-hander in “The Sessions,” and Nicole Kidman, the sparky catalyst for all manner of strange goings-on in “The Paperboy.” Among the favored contenders squeezed out by Kidman's surprise nod is Ann Dowd, the moral conscience and, in some critics' eyes, the outright protagonist of “Compliance.” The character actress's profile, however, is low enough for a supporting campaign not to seem too improbable – and the Independent Spirits and National Board of Review voters have been among those willing to play along.

Over in the Best Supporting Actor race, Philip Seymour Hoffman is widely viewed as one of the leading contenders – not least because he arguably should be a leading contender in another sense, as the duet partner of SAG-ignored Best Actor hopeful Joaquin Phoenix in the unromantic male love story that is “The Master.” Phoenix may lead on screen time, but I'm among those who finds it hard to argue that Hoffman, the tonally balancing yin to the younger man's wild-eyed yang, is supporting his co-star so much as leading him on – or perhaps vice versa.

It's an indistinct line, though not so blurry that Hoffman's nomination is under threat – which is more than can be said for Christoph Waltz, deservedly earning critical plaudits for playfully bromancing Jamie Foxx in “Django Unchained.” A buddy film for most of its substantial running time, “Django” seems positively led by Waltz for lengthy early stretches until Foxx's title character grows into his own revenge narrative. The actors and characters alike are engaged in a partnership, but The Weinstein Company has opted to run Waltz in supporting – a ploy that would be tidier if the film didn't boast juicy, more self-evidently subordinate roles for Leonardo DiCaprio and Samuel L. Jackson, creating a pileup of contrastingly scaled supporting actors uniformly vulnerable to vote-splitting.

You can question the strategic wisdom behind some of these already questionable calls – why Helen Hunt's team, for example, decided to trade what looked a likely Best Actress nod for a supporting bid she almost certainly can't win remains a head-scratcher to me – while also understanding why an already disadvantaged candidate like Dowd would choose the path of less resistance.

Though we all go there on occasion, it's a mistake to get too righteous about a game where no one is seeing quite the same goalposts. (Okay, sometimes we do: the 2003 case of young Keisha Castle-Hughes, campaigned in supporting by her overly cautious studio, is an example of category fraud so egregiously dishonest the Academy took it upon themselves to correct it.)

Subjective definitions of what constitutes a lead performance are many and varied, variously taking in such considerations as ownership of the narrative, degree of character change and/or influence, point of view and relationship to that of the audience, or, for the more literal-minded, simple, stopwatch-monitored screen time. A few seem to be of the opinion that a film can only have one lead; others argue whether democratic ensemble pieces are all-lead or all-supporting propositions.

Amid all this, some might ask if it even matters, as long as good performances are finding recognition in some dimension – I confess I cheered Nicole Kidman's nomination this morning, even if I believe it came in the wrong category. My greedy favoritism notwithstanding, however, I must insist that it does matter. The more room voters make for lead or borderline-lead stars across all acting categories, the fewer opportunities they leave for genuine fringe players to find career-enhancing recognition – and the less they encourage us to spot the subtler details of a successful film's construction.

Nicole Kidman's aces in “The Paperboy,” sure – but so is Macy Gray, in a less central but no less integral part that nonetheless suffers in a side-by-side competition. Is Helen Hunt so superior to the wonderfully wry Moon Bloodgood in “The Sessions” that the latter doesn't even rate a mention in the film's FYC ads – or are the actresses' roles too disparate in scale to merit a fair comparison? If Philip Seymour Hoffman is a supporting actor in “The Master,” then what is Jesse Plemons, so economically piercing as his plainly wary but superficially obedient son? (Should Best Sub-Supporting Actor become a new Oscar category?) Mileage will vary as much on the question of what roles are award-worthy as what roles are leading, but let's take care not to let the two questions overlap.

Check out my updated predictions HERE and, as always, see how Kris Tapley, Greg Ellwood and I collectively think the season will turn out at THE CONTENDERS.