Sandra Bullock, George Clooney, and Meryl Streep all had one good movie and one bad movie in 2009

Sandra Bullock, George Clooney, and Meryl Streep are all on the Oscar short list for their work in The Blind Side, Up in the Air, and Julie & Julia. And with good reason: They’re all terrific. They are not, however, likely to get Oscar love for their work in All About Steve, The Men Who Stare at Goats, and It’s Complicated. Also for good reason: Steve was awful, Goats was idiotic, and It’s Complicated was, to my mind, so posed and shallow that teams of world-class thespians working ’round the clock couldn’t muster much critical approval from anyone outside the Golden Globe-juggling comedy act known as the Hollywood Foreign Press Association.

And yet, in each film Bullock, Clooney, and Streep were all equally, recognizably themselves — three of Hollywood’s top movie stars in good stuff and crap in the same year. Which is why my favorite awards-season talking point is that the difference between an average performance and an award-magnet performance — assuming the actors in question have any talent — has very little to do with skill or craft. Instead, it has everything to do with everything else.

Four everything elses, to be specific. And they’re all intertwined with one another: the clarity with which the character is conceived; the strength of the movie in general; the appropriateness of the casting; and the magic of old-fashioned star power. (Star power, by the way, isn’t only the province of A-listers. Unknown actors — such as young Carey Mulligan in An Education or Gabourey Sidibe in Precious — can come from nowhere and command the screen with the same instantly recognizable authority.)

Bullock, Clooney, and Streep were all handed gift gigs when they were asked to play a Southern family woman, a jaded corporate head-chopper, and Julia Child. And then well-knit screenplays and good direction placed those characters in sharp focus. As for the serendipity of casting, well, look what gusts of pleasure George Clooney whipped up when he riffed on his famously charming persona of sleek, offhand, crinkle-eyed bemusement to create that fictional corporate downsizer. The role improved Clooney’s game, just as Clooney improved the movie’s game, a win-win situation that he alluded to in a recent EW interview: ”I remember I did Batman & Robin, and the next film I did was Out of Sight. Batman & Robin is not a very good film, and I’m not very good in it. Out of Sight‘s a very good film and I’m good in it. I wasn’t that different as an actor. It was a couple of months later. I didn’t learn everything you need to learn. It was about the rest of the elements.”

And as I bet Clooney would agree, you don’t even need a Clooney if all the other elements are in place. Quentin Tarantino — a master of inventive casting — thinks outside the box by giving the crucial role of Nazi colonel Hans Landa in Inglourious Basterds to Christoph Waltz. The veteran Austrian character actor is now, deservedly, a star. Meanwhile, director Kathryn Bigelow put together an ensemble of less-than-famous actors for her taut, jagged war picture The Hurt Locker — and kept the audience focused on soldiers rather than the actors playing them. The result? The previously less-than-famous Jeremy Renner is now an awards-season regular.

In the coming weeks, Oscar politicking aimed at voting members of the Academy will reach its peak. But regular nonvoting ticket-buying moviegoers can enjoy themselves by remembering that even the best actors can be crappy when they’re in crappy movies. That it’s just as exciting to discover a new, talented actor in a good movie as it is to watch a familiar favorite pull off a screen triumph. That while acting is a combination of skill and art, an award-worthy performance is an amalgam of science, technology, and luck. And finally, that what you think of as a great performance has as much to do with how much you enjoy the whole movie experience — the plot, the music, the quality of the snacks, the smell of the moviegoer to your right — as it does with one actor’s ability to cry and another’s to kickbox or crack eggs. Yes, they’re only movies, but sometimes everything works. That’s why no matter how many times you’ve seen them do it, it’s still ridiculously satisfying to hear Sandra Bullock laugh, watch George Clooney smile, or listen to Meryl Streep say, ”Bon appétit!”