Dame Helen Mirren inhabits the intimidating persona of Queen Elizabeth II in this dramatization of the private lives of Britain's leaders in the days immediately following Princess Diana's 1997 death.

Mirren has had some practice playing royals: The Queen follows right on the heels of Tom Hooper's Elizabeth I, an extraordinary 2005 TV miniseries about the latter years of the first Queen Elizabeth, in which Mirren also acted in the title role. Her experience shows, and whatever The Queen is worth as a whole, Mirren's performance is convincing to the point that it's almost eerie to watch, portraying as it does the private life of one of the most carefully protected public figures in modern times.

Director Stephen Frears (Mrs. Henderson Presents, High Fidelity, The Grifters) keeps the kid gloves on in his treatment of the royal family and the Blairs, presenting what amounts to an apology for the missteps and insensitivity of the crown in the wake of national mourning for the ill-fated Diana. We are granted backstage access as the queen, her husband and her grandsons (the boys are mercifully spared any extended onscreen appearances in the film) lie low in the countryside after the accident, inciting public outrage at the queen's refusal to address her subjects. The central dilemma is the question of whether Elizabeth will evolve with the times and reach out to her people, or maintain her dignity by refusing to participate in a media frenzy.

Frears' uneven yet artful directing marks the continued development of an extremely talented filmmaker. His able use of montage to weave together gripping news footage with staged dramatics is unparalleled—even in a period marked by big-budget attempts at docudrama and dramatization (United 93, World Trade Center)—and the effect of Frears having fused these two elements together lingers long after the credits roll.

Actor Michael Sheen is nearly as winsome and earnest as Prime Minister Tony Blair himself appeared to be as he shouldered the mantle of power in the shadow cast by the tragic Paris car crash. Frears' depiction of Blair as the unwitting beneficiary of glowing public opinion after Diana's death is particularly difficult to swallow. One understands giving Queen Elizabeth the benefit of the doubt regarding her personal motives during those difficult times, but to imply that Blair was either selfless or politically naive is ridiculous. It seems plausible that the royal family would wish to lick their wounds in private after the mother of the future king was killed, but it's a stretch to expect an audience to sympathize with the prime minister at the very moment of his ascension to power. Blair is hardly Winston Churchill, and Diana's death, though tragic, was hardly a political calamity for him and his party.

Perhaps this is where The Queen begins to unravel. Despite an astonishing—and Oscar-worthy—performance by Mirren, and the candor and ingenuity with which Frears approaches his subject, The Queen loses its objectivity when it turns to Blair and begins to resemble agitprop. Frears would have been better served by reserving his sympathy for the monarch and letting Blair fend for himself.

Opens Friday, Oct. 27, at Fox Tower.