Saoirse Ronan already has delivered a number of Academy Award-worthy acting performances, as evidenced by her three nominations to date, so it’s depressing to think she might finally win one for a film as bland and disappointing as “Mary, Queen of Scots.”

This film is based on British historian John Guy’s well-received biography, “Queen of Scots: The True Life of Mary Stuart.” Like the book, the film helps dispel the popular myth that Mary I of Scotland was either a helpless ingenue or a grasping harlot.

Ronan is convincing in her sympathetic portrayal of Mary as a canny, formidable ruler who fails only due to the faithless, mediocre men upon whom she’s forced to rely.

But the talented supporting cast is given so little material of their own to work with.

Guy Pearce goes into scheming puppetmaster autopilot as William Cecil, advisor to Queen Elizabeth I, who is Mary’s rival to the­ English throne. Former “Doctor Who” David Tennant relies on little more than his brogue and the volume of his line delivery to play Scottish Protestant cleric John Hook, who condemns the Catholic Mary as a veritable whore of Babylon.

And while actors of color such as Adrian Lester and Gemma Chan are a welcome sight here, considering how often such period-piece dramas tend to whitewash history, they’re not provided fully rounded characters worthy of their talents, and instead serve as little more than plot devices and expository prompts.

Worst of all, this film utterly wastes Margot Robbie, also a deservingly Academy Award-nominated actress, as Elizabeth, who appears here as a cipher.

The narrative pays lip service to the notion, voiced by Mary onscreen, that women in power should share a solidarity of sisterhood, rather than allowing the men around them to bring them down by pitting the women against each other. And yet, the completely historically inaccurate denouement of having Elizabeth and Mary meet in person cements the underlying sexist message of the story all along.

Because Mary was beautiful and had a child who would become heir to the throne, the audience is told she is to be admired more than Elizabeth. By which I mean, the film literally has the envious character of Elizabeth herself say this, in dialog and voice-over narration directed to Mary.

To hammer the point home, Robbie plays Elizabeth as pitifully diminished, not only by her lack of children, but also by the pox scars that prompt her to cover her previously flawless face with clownish pancake makeup.

There are some interesting revisionary takes on history here. While it’s a matter of record that Mary’s second husband (and first cousin), Henry Stuart, took part in killing her confidant, David Rizzio, the film suggests it was not to cover up a rumored affair between David and Mary, but rather to conceal evidence of an affair between David and Henry.

And although Mary’s son, James, did become the first dual king of Scotland and England, it’s more than a bit amusing to see Mary touted by this film as a model of religious tolerance. Given the Protestant ascendancy in Scotland at the time, it was arguably more a matter of political pragmatism, and James would go on to popularize witch hunts as king.

This is the kind of pretentious, pseudo-historical drama that gets made to win Oscars, and such films succeed at their aim because the actors who star in them have typically been snubbed for so many previous superior acting performances that the voting members of the Academy say to themselves, “Oh, it’s their time now.”