If it were announced that “Hamilton” had sparked the single largest day of ticket sales in the history of a long-established theater company, no one would so much as look up from their smartphones. ¶ But “Camelot”? ¶ Yes, “Camelot.” Such was the result for Shakespeare Theatre Company, on the day three weeks ago when reviews appeared for the august Washington troupe’s revival of the 1960 musical by Alan Jay Lerner and Frederick Loewe. The surge in sales not only prompted a week-long extension of the show, to July 8, in the company’s bigger theater, 774-seat Sidney Harman Hall, but the ticket bump also exceeded by 25 percent the previous record, for a 2009 production of “King Lear” starring Stacy Keach, according to company officials.

That’s a remarkable spike for a theatrical chestnut without a box-office-drawing name to spur a buying spree. Three excellent performances inhabit the core of director Alan Paul’s revival: Ken Clark’s King Arthur, Alexandra Silber’s Guenevere and Nick Fitzer’s Lancelot — and more in a minute on Fitzer’s work here, in an especially stunning company debut. But some other factors have to be playing active roles in driving demand. And one of them just might be that “Camelot” is a wistful, inspirational allegory befitting a dark time for America, a musical about a leader of conscience and a commitment to the ideals of better, fairer government. Not to mention, a reminder of a bygone administration headed by John F. Kennedy that, at the time, adopted the musical as an avatar of its own aspirations.

It’s something that those involved in the production are giving some thought to it, as well, as they celebrate the production’s success. Shakespeare Theatre is far better known for its Shakespeare than for the musical revivals it began integrating into its seasons in 2010, with a robust mounting of Leonard Bernstein’s 1956 “Candide.” The idea was to broaden the company’s programming but also to adjust to a marketplace in which the appetite for show tunes exceeds that for iambic pentameter.

We’re often scouring Shakespeare’s work for its contemporary resonances, of course. In that vein, Paul, the company’s associate artistic director, says what he discovered as he looked for ways to tell this richly melodic story of the formation by Arthur of the legendary Knights of the Round Table, was that there were urgent ideas about a just society embedded in the tale.

“The love triangle is a big part of it, but it’s really about democracy,” Paul says of the show, which traces Arthur’s disillusionment as his grand plan dissolves with Lancelot and Guenevere’s romantic betrayal — and then has his hopes restored by the entreaties of a child inspired by Arthur’s dream. “I imagined what Obama might have felt like when the other side comes into power, and he wonders, ‘Did anything I say matter?’ ”

In the tale, too, of a man of democratic inclination who is energized by the possibility of transforming the lives of others, the director found he had stumbled onto another relevant theme. “People want to talk about what is going on in the world in a non-ironic way,” Paul avers. “The musical stands for an idea of what this country can be.”

This is a potent argument for grasping the renewed popularity of a musical about ideals in a town that is often thought as overrun by cynicism. Chris Jennings, the Shakespeare Theatre’s executive director, says that he believes the organization has been successful, too, in choosing musicals in harmony with the mission of a company that mines historical traditions. “Our core audience does not feel a departure from what we do,” Jennings says of the once-a-season segue to musical theater. “And then we get the added value of a lot of new people coming into our doors.”

The cast is intrigued by why Paul’s “Camelot” is working so well, too. Which brings us to Fitzer, an opera-trained 33-year-old actor, originally from Livonia, Mich., who supplies a beguilingly virile sheen to Lancelot and his signature songs, the comically self-confident “C’est Moi” and the dreamy “If Ever I Would Leave You.” Were he a better-known performer, his portrayal, it’s safe to say, would be causing the cash registers to ring, too.

Fitzer, who now lives in New York, says that Paul encouraged the actors to develop a sense of these legendary rulers and knights as psychologically complex beings, and that helped him find his way. “Alan gave us the opportunity to get deep into the throes of who these character are,” he says, adding that up to now, the companies he’s worked with did not have the resources of a Shakespeare Theatre for dramatic exploration. “I’ve never done a show where they could afford to do a week of table work to break down a script. And it was a joyous experience.”

If this production, with its sleek visual aesthetic overseen by set designer Walt Spangler, comes across as better equipped for the realities of 2018, it might also be because Paul negotiated with the estate handling Lerner and Loewe’s musicals to reassign some lines. Now, for instance, the plan for a new order of chivalry, emanating originally from Arthur, is hatched collaboratively: Guenevere has as much to say about it now as her husband. “That gives a little more flexibility,” Paul says, “for a director to reinterpret it.”

The sense of a fresh concept is revealed in the work of Fitzer, who says he looked for ways to communicate an idea of Lancelot as an evolved sort of romantic hero. “I wanted to make him feminist in a lot of ways,” he says. “He’s self-assured but he only initiates with Guenevere when he knows that she returns his love.” He had a head start on this path at home. “It’s my mother’s favorite musical,” he says, and although his parents, Patti and John, could not have predicted he’d end up playing Lancelot, they recognized early on that his path was going to be a tuneful one. “Basically, it’s what my mother did for me,” Patti Fitzer says by phone from Michigan. “My mother gave me wings. She raised me and said, ‘Okay, go and live your life.’ And right from the get-go Nick was telling us, ‘I’m out of here.’ I knew we would always be here for him.”

You sense Fitzer’s passion for the project when you see him as Lancelot, just as you do with Clark and Silber, in their equally pleasurable turns. So smart casting is undergirding whatever combination of factors has made this revival so popular. An element of the ephemeral is always part of the formula in a hit, too. So Fitzer can’t entirely rule out divine intervention.

“I don’t know how religious I still am,” he says, “but I asked God for this role.”

Camelot, music by Frederick Loewe, book and lyrics by Alan Jay Lerner. Directed by Alan Paul. Tickets: $44-$118. Through July 8 at Sidney Harman Hall, 610 F St. NW. 202-544-1122 or shakespearetheatre.org.