The position is once again empty (though not for long) at the beginning of “Harry Potter and the Order of the Phoenix,” the fifth movie in the increasingly ominous series adapted from the works of J.K. Rowling. The film opens in suitably grim fashion, with a pair of Dementors attacking Harry (Daniel Radcliffe) and Dudley Dursely. Harry’s use of magic in front of his Muggle cousin prompts a formal inquiry by the Ministry of Magic, and although he’s vindicated, other sinister things are afoot. Voldemort (Ralph Fiennes) is back, but the Ministry and a substantial percentage of the magical community, unwilling to face the ordeal of fighting him again, are ignoring his return.

It’s also a new year at Hogwarts, where Harry is being looked at askance by his classmates, many of whom doubt his story about the death of Cedric Diggory (you’d think the fact that he’d won them the House Cup, two Quidditch Cups, and saved their asses from a basilisk would earn him a little slack, but evidently not). The students also have to contend with – surprise – a new Defense Against the Dark Arts instructor: Dolores Umbridge (Imelda Staunton). An appointee of the Ministry, Umbridge was one of the sole tribunal members who voted to expel Harry, and refuses to teach the students anything useful. Further, after she becomes the school’s “High Inquisitor,” she implements a series of restrictive edicts designed to keep the school population docile. This puts her increasingly at odds with Headmaster Dumbledore (Michael Gambon), who’s also on the outs with the Ministry.

Things start off slowly. Very slowly. I’m told by those who’ve read “Phoenix” (I haven’t) that a sizeable chunk of the book is occupied with the members of the Order of the Phoenix (a group formed by Dumbledore back during Voldemort’s first power grab) sitting around and plotting their strategy. If so, the movie is a pretty faithful adaptation. What we have is a lot of set-up: Umbridge clamps down at school, Harry teaches a group students calling themselves “Dumbledore’s Army” how to combat the forces of evil, and Sirius Black (Gary Oldman) and “Mad Eye” Moody (Brendan Gleeson) get ready to do battle with the bad guys. In the meantime, everyone talks about the ominous portents obviously intended to hold our interest for another two films.

Which begs the question: was this movie (or the book, for that matter) really necessary? Everybody knows that Harry and Voldemort are going to have to square off eventually, that fact has been shoved down our throats since book one. But after finally showing us the bad guy in “Goblet of Fire,” making us sit through two more movies of hand-wringing and Harry struggling against the Dark Side of the Force Voldemort’s influence seems a bit obnoxious. Especially when – as in “Order of the Phoenix” – relatively little happens.

Until the ending, that is, when all the hemming and hawing is finally put to rest and we get some hot wizard on wizard action. Welcome as it is, the climax is rushed, and a certain significant character’s demise flashes by as though new director David Yates temporarily forgot he had to include it. A veteran of British TV, Yates’ style seems to consist solely of cribbing the look of directors Alfonso “Prisoner of Azkaban” Cuaron and Mike “Goblet of Fire” Newell’s efforts without paying attention to their skill at setting the pace, while new screenwriter Michael Goldenberg (replacing four-time scribe Steve Kloves) shows no interest in tightening things up. “Order of the Phoenix” is the shortest Harry Potter movie so far, but feels like a James Michener miniseries.

The film still features top-notch talent in the adult cast, underutilized though they may be. Gleeson has barely a dozen lines, while Dame Maggie Smith, David Thewlis, and Emma Thompson have little more than cameos. Oldman fares a little better, as does Staunton, who has the movie’s juiciest role. Alan Rickman’s Snape – my favorite character in the series – also figures prominently, and I’ll admit an unhealthy attraction to new villainess Bellatrix Lestrange (Helena Bonham Carter).

The younger actors are another story. Part of the problem is that Goldenberg’s script doesn’t require anyone but Radcliffe to stretch himself. Even so, Emma Watson and Rupert Grint, who seemed like they were on the right track after “Azkaban,” aren’t asked to do much besides fret after Harry, and that gets old in a hurry.

After the leaps forward made in the last two movies, “Harry Potter and the Order of the Phoenix” is something of a letdown. Previous statements aside, I understand Warner Bros. has to set the table for “Half-Blood Prince” and “Deathly Hallows,” but too much of “Phoenix” is filler. And with only two movies left, we better get to the main course in short order.