Around 2:30 Sunday afternoon, Zubin Mehta had likely just finished conducting Siegfried’s heroic “Funeral Music” as part of his Los Angeles Philharmonic Wagner program at Walt Disney Concert Hall. At that same time, several miles down the 710 Freeway, comic book aficionados were no doubt celebrating superheroes galore at Long Beach Comic Expo in the convention center, while opera fans next door at the Beverly O’Neill Theater had taken their seats for Long Beach Opera’s new production of Purcell’s “King Arthur.” There is a good chance Donald Trump was flexing heroic tweeting fingers that moment as well.

And in some startlingly deep-time, parallel reality, mirrorverse way, all these activities happened to be connected.

You may recall that John Boorman’s 1981 “Excalibur” (arguably the best of King Arthur movies, excepting, of course, “Monty Python and the Holy Grail”) grabs immediate attention by opening with Siegfried’s “Funeral Music.” Wagner, after all, got his sword-in-the-stone idea from the Arthurian legend.

Meanwhile, Long Beach Opera, as ever priding itself with radically rethinking repertory, has done a full refashioning of the first great “King Arthur” opera (there aren’t many, but Chausson’s “Le Roi Arthus” is a neglected beauty). Arthur here becomes the comic book delusional fantasy of a pudgy, narcissistic, emigrant-phobic politico requiring psychiatric treatment.

Well, you’ve got to do something with this 17th century British “semi-opera.” There is Purcell’s fetching score with some of the sweetest music ever to come from the fairest isle. There is poet John Dryden’s libretto. In what had been at the time a Brexit from the concept of European opera, the two seldom meet.

A long, florid play, “King Arthur or The British Worthy,” centers not on Camelot but Arthur’s Saxon campaign. Merlin has but a bit part. In five lavish acts, music, dance and fantastical stage apparatus is used more for theatrical spectacle than drama. There are pagan ceremonies, lusty shepherds, patriotic odes, love songs, nature at its business, a frost scene that has to be heard to be believed and a major influence on late 20th century British minimalism.

LBO chocks all that. Its “King Arthur” in this non-proscenium small theater opens with a stage empty but for a bed. A small orchestra — the esteemed early music ensemble, Musica Angelica — is seated behind a large screen on which there will be video projections.

A man in a suit enters. He strips to his underwear. His T-shirt is red with a large A in a circle. He picks up a comic book. He switches on a TV and hears the latest about plans for our southern border. The president is suggesting electrifying a wall or shooting migrants in the leg.

“These comments sound like they are out of a biting satire about a xenophobic leader,” the conductor, stage director, designer and LBO artistic and general director Andreas Mitisek writes in the program book, “but they are the real scary thoughts voiced by a President of the USA.

“With our REDUX of King Arthur, we use satire to comment on the political climate around us.”

Then, again, Dryden begins the original spoken prologue to his play lamenting a “Dearth of Wit in this dull Town / When silly Plays so savourly go down.”

Arthur King is a patient at Camelot O’Neil, a behavioral residence mental health unit. His sexy nurse is Gwen E. Veer. His buddy is another patient, Lance E. Lott. Doc Oswald runs the dubious joint.

Mitisek then takes apart the opera, adapting Purcell’s music to fit new circumstances and a completely new theatrical structure. His cutup rearranges, revises, reorders and reduces Purcell’s score. The occasional Dryden line is retained, but much of the sung text is new. Five acts become a single uninterrupted one under two hours.

Our schlumpy, Trumpian Arthur thinks he can save the world from aliens. He can be ridiculously pompous, Drydenesque even. He can also be sympathetically vulnerable.

There is no dearth of wit here as a silly play adapted by the satirical collective, Culture Clash, goes savourly down. What prevents many crude antics from getting too annoying — and pretty much takes the bite out of the political satire — is Purcell’s irresistible score and an outstanding cast.

Marc Molomot is a hugely charismatic Arthur. A superb actor, he is as much Jimmy Durante as a Trump wannabe, capable of winning our affections with a depth of expression once he begins to sing. Much can be equally said of Jamie Chamberlin’s feisty, funny Gwen; of Cedric Berry’s magnetically cheesy Doc Oswald; of countertenor Darryl Taylor’s snappy Lance. With this cast you simply can’t go wrong.

For his part, Mitisek leads a musically excellent performance and, in yet another of his hats, contributes effectively goofy video imagery.

In the end, Purcell wins, Dryden loses, Trump gets a pass and British opera really Brexits. Could it be that this “King Arthur” is not such an alternate reality after all?

Long Beach Opera ‘King Arthur’

Where: Beverly O’Neill Theater, 300 E. Ocean Blvd., Long Beach

When: 7:30 p.m. Sat. and 2:30 p.m. Sun

Tickets: $49 – $150

Information: (526) 470-7464 or longbeachopera.org

Running time: 1 hour, 45 minutes