Jeremy Strong and Michael Imperioli duke it out on Broadway

There is an unintentionally funny line in the compelling revival of “An Enemy of the People” that opened Monday night on Broadway.

“We’re behind you like a wall!” a small-town newspaper printer named Aslaksen tells Dr. Thomas Stockmann, a scientist who has just discovered that the water in the local mineral baths is poisonous.

Although this conversational new adaptation of Henrik Ibsen’s classic play is by Amy Herzog, some version of those words has been spoken ever since it premiered in Norway back in 1882.

So, why are they suddenly getting grins?

Circle in the Square Theatre, where “Succession” star Jeremy Strong and Michael Imperioli from “The Sopranos” are facing off nightly, is situated in the round with audience members on all sides.

There are no walls.

And, following suit, the printer’s promise is totally empty. Hardly anybody, least of all him, will really remain behind poor Dr. Stockmann in the end.

Twenty minutes after that statement of camaraderie is uttered, support for the doctor’s righteous cause all but disappears. He tumbles from town hero to an ostracized villain for merely pointing out that tourists are bathing in disease-causing bacteria.

But, hey, it’s not called “Best Bud of the People.”

“Enemy,” which last played Broadway 12 years ago, is the sort of not-quite-ripped-from-the-headlines play that could be about any fill-in-the-blank issue that’s on the viewer’s mind that day. It’s relevant by design.

Exhibiting restraint — well, almost — director Sam Gold avoids making obvious modern parallels to needlessly buttress its potency. David Zinn’s costumes are 19th century chic, and the firm dots has designed a period set of weathered, white wood and evocative oil lamps.

We are very much in Norway, until an unfortunate 10-minute “pause” before the second half, when we are very much at a bar in Murray Hill. More on that daffy diversion later.

Who better to take the world’s cruel punches than Strong, who last year wrapped up playing aggrieved Kendall “I’m the eldest boy!” Roy on the TV series “Succession”?

As Thomas, Strong looks every inch a martyr, albeit a flawed one who is rich enough that he doesn’t bother learning his own maid’s name. The actor is sensitive but certain, nice but arrogant, pretentious but likable, quiet but commanding.

And the intimate Circle is ideal for Strong’s more focussed and introspective brand of acting.

But this “Enemy” is, of course, a battle of two HBO titans: Kendall versus Christopher.

Imperioli plays Mayor Peter Stockmann, Thomas’ fiscally conservative brother with an ax to grind. Forever annoyed with his sibling, now he’s furious that his damaging findings, if published in the People’s Messenger newspaper, could jeopardize the booming economy and burden taxpayers.

The actor is, in a fraternal way, Strong’s opposite. His Peter is imposing, quick-tempered and, with spiky, slicked-back white hair, Tim Burton-style scary.

Avoiding the play’s pitfalls, Imperioli and the rest of the cast refrain from going overboard with shouts and violent lunges. They force the audience to listen closely to their arguments rather than cause us to quickly tone out the angriest voices.

That’s not to say that “Enemy” doesn’t take sides. Thomas Stockmann is the sole good guy here, as usual.

And Strong is surrounded by great actors.

There are the brash young radicals at the newspaper: editor Hovstad (Caleb Eberhardt, an ideal idealist) and deputy Billing (Matthew August Jeffers, fun then threatening), alongside the proudly moderate Aslaksen (Thomas Jay Ryan, venomous).

Herzog has nixed the part of Thomas’ wife. In fact, she’s killed her off, maybe to make the doctor a more sympathetic figure and provide him with a drive to save his community that’s more human than medical duty.  

Now, that role is subsumed by his schoolteacher daughter Petra, played by Victoria Pedretti in a strikingly vulnerable, old-world Broadway debut.

Excellent performances like these are all this play needs to be forceful and pulse-pounding.

But Gold, whose Broadway “Macbeth” starring Daniel Craig was a bells-and-whistles disaster, nearly bungles it by serving the audience free shots of Linie Aquavit between the first and second halves from a hopping bar onstage. The otherwise riveted man next to me said, “This is so stupid.” Twice.

I’m sure there is a high-minded rationale for the pop-up pub. Perhaps it’s there to confront us with our own hypocrisy, or lull us into a false sense of security before the untethered town meeting where Thomas is attacked. 

Whatever the reason, the silly trick flattens the tension the cast built and leaves it up to Strong to pick up the pieces.

He ably does, thank goodness, and prevents his director from becoming the enemy of the play.