How long are our attention spans? It’s a question worth asking as the manifold dramas and traumas of the Trump presidency tend to overshadow one another. (Was Donald Trump’s last rally just this week? Was “Fire and Fury” released this year? How soon are the midterms, again?)

“The Family Business,” a Showtime documentary short broadcast Sunday night, prompts this question more than perhaps any other. It focuses on the New York Times report, published on Oct. 2, into Donald Trump’s family finances and the degree of fraudulence that padded both his claims that his father had given him a fairly small loan, paid back with interest, and his dealings with the Internal Revenue Service. Cameras recorded the moving and strangely mundane scene before it went live, with reporters stuck in a midtown Manhattan conference room, as tense as actors waiting for opening night of a play.

According to “The Family Business,” the investigation was prompted by reporters’ curiosity after the provocative and incomplete Rachel Maddow segment that aired last March on a partial 2005 Trump tax return. Over the course of a half-hour, we track 18 months in reporters’ lives as they chase down the story. By dint of its running time and its focus on a single, hard-to-nail-down story — as opposed to the four hours and diffuse, ever-shifting focus of “The Fourth Estate,” Showtime’s 2018 docuseries about the Times’ political reporters — “The Family Business” feels less granular than it might. “The Fourth Estate,” focusing as it did on people working the ins and outs of a beat that constantly demanded copy, lended texture and personality to the daily briefing; “The Family Business” could never be as interesting as the 14,000-word story whose origin it documents.

But, more crucially, the Times story on Trump’s taxes also feels less vital to document than do the daily Trump-said-this, Trump-did-that stories “The Fourth Estate” spotlighted. Those are still, even just a month before Trump’s midterm, the pulse-igniting and narrative-moving diary of any news consumer’s days. What “The Family Business” does most effectively is show just how much Trump, through force of personality and through radioactive waves of malfeasance, has come to define the national narrative. Susanne Craig, a career-long financial journalist, marvels that she’s on the presidential beat at all, before remarking, “Money, power, greed: What more could a reporter want?”

And that’s what readers seem to want, too. Earlier in the evening, Showtime broadcast an episode of its political docuseries “The Circus” that was focused on the recent fight over the confirmation of Justice Brett Kavanaugh. Your reaction to the previous three words — the name of the controversial figure now given a lifetime appointment to set the nation’s legal agenda — should indicate how vividly this dispatch of the week overshadowed a story about reporters doing careful, methodical, worthy work. Throughout the campaign, so many people wanted to see Trump’s taxes; finally given extensive access to the information, so many find themselves torn away in favor of the incandescent blast of the latest national psychosis.

“The Family Business” is a worthy portrait of journalists doing work that is vital and necessary to our understanding of the man elected as president. But like the work it documents, it fits in an askew manner to its very specific moment, and may have no place in its era. For this alone, it’s worth watching; for this alone, if the viewer is willing to devote thirty minutes to a story that’s already been digested and moved past on the national stage, it may well break your heart.