Even Benedict Cumberbatch (top), alas, can’t fully explain Brexit.

Cumberbatch does give it his best effort, however, in a new HBO film of the same name. Brexit, a ripped-from-the-headlines drama, gets its U.S. debut Saturday at 9 p.m. ET.

The film couldn’t be more timely, arriving at the end of a remarkable week when British Prime Minister Theresa May’s latest effort to sell a Brexit deal to Parliament got totally thumped – and 24 hours later the same Parliament turned around and said, yes, Mrs. May, we want you to remain our prime minister.

Even in the Trumpian age of weird politics, Brexit has stood out as unusually discombobulated.

Brexit the film, wisely, doesn’t attempt to follow the whole crazy path. It focuses only on the 2016 campaign that ended with British voters choosing to leave the European Union.

British Exit = Brexit.

Cumberbatch, swapping his signature old-school hairstyles for almost no hair at all, plays Dominic Cummings, the strategist who directed the successful “Leave” campaign.

Rory Kinnear (left) plays Craig Oliver, his counterpart who led the failed “Remain” effort.

Most of the film’s attention, logically enough, falls on Cummings, suggesting his brilliant strategy won the day more than any failing of Oliver’s lost it.

The ominous part comes when Brexit suggests part of Cummings’s strategy relied on two shadowy sources of help: Robert Mercer, a conservative Texas billionaire who was the largest single donor to the campaign, and Cambridge Analytica, a leading-edge data mining outfit that promises Cummings it can identify and target three million disenchanted people who ordinarily don’t even vote, but here might be persuaded to vote leave.

Cambridge Analytica has been accused of practicing shadowy business, primarily by illegally mining data from unknowing users of social media like Facebook. Cambridge Analytica has faced similar charges for its role in the 2016 Donald Trump campaign.

Brexit also includes a Cambridge Analytica defender who notes that online identification and targeting of voters has been around for a decade or more. Cambridge Analytica perhaps just did it more effectively, which opens the door to looking at Cummings’s work in a different light.

Maybe the “Leave” campaign didn’t rewrite the political rule book. Maybe it simply executed the traditional rulebook well, utilizing modern tools.

For starters, Cummings focused the campaign’s official message on the most appealing and least controversial arguments: that leaving the EU would save Britain money and allow Britain to set more of its own policies.

Now yes, Cummings fully understood that much of the anti-EU sentiment was rooted in something else: fear of unrestricted immigration, which the EU was seen as promoting.

So while Cummings left immigration almost unmentioned in official campaign literature, he did not discourage several independent Leave advocates from pounding that message early and often.  

Against the advice of several old-school Leave advocates, including members of Parliament, Cummings dismissed almost all traditional tactics like lawn signs. He diverted most resources and time to online operations, which he saw as a more persuasive path to hearts and minds.

Similarly, perhaps, Brexit keeps its own focus narrow enough that it never really gets into broader issues like whether there was a “populist” wave sweeping the whole globe around the time of the Brexit vote.

If there was such a wave, Cummings rode it nicely and gladly. The man himself, skillfully portrayed by Cumberbatch, comes off as a political iconoclast. He believes Britain should leave the EU, but more than that he believes the old guard of politics needs to be toppled, in order to build something better on the ruins.

A coda to the film says the real-life Cummings rapidly became so disillusioned with the political aftermath of the Brexit vote that he walked away.

It isn’t exactly an echo of Tom Lehrer’s song “Werner Von Braun,” in which Von Braun sings, “Once the rockets are up, who cares where they come down? / That’s not my department… .”  But it has a little of that feeling – that Cummings tossed the grenade and then skedaddled, letting everyone else deal with the consequences.

Brexit includes one wholly fictional scene of Cummings and Oliver getting together for a drink and warning each other about the consequences of what they’re doing.

Cummings warns Oliver that he’s not listening to the voices and the real frustrations of the people and that he doesn’t even know how to reach them to ask.

Oliver counters that whatever Cummings is tapping into, he’s unleashing dangerous unguided missiles no one can control.

They both make good points, and to the extent they both fear the Brexit campaign was cooking up a formula for political chaos, that’s exactly the dish to which real-life Britain is now sitting down.