Quinta Jurecic is the managing editor of Lawfare, an online publication on national security and law.

What you think of the new book by Fusion GPS founders Glenn Simpson and Peter Fritsch — better known as the men behind the Steele dossier — will depend almost entirely on what view you take of the dossier itself. Is your position that the infamous document is a sham product cobbled together by Democratic operatives out to smear the president? Simpson and Fritsch’s “Crime in Progress” is unlikely to convince you otherwise. Are you still holding out hope for the release of a lewd video of Donald Trump in a Moscow hotel room, so tantalizingly described in the dossier? “Crime in Progress” won’t sate your desire for the “pee tape,” but it also won’t disprove the tape’s existence if you want to believe in it.

The dossier burst onto the public scene in January 2017, when BuzzFeed News published the document that much of Washington had been whispering about for months: a private intelligence report, compiled by former British spy Christopher Steele, documenting alleged links between Trump and the Russian government. Trump, then president-elect, declared the dossier to be “fake news.” His supporters began attacking Steele and the private research firm that had hired him, Fusion GPS, zeroing in on the fact that Fusion’s work was paid for in part by a law firm representing Democratic Party institutions. Almost three years later, the dossier is still a touchstone for the president’s supporters: Republicans have grilled witnesses about it during the past two weeks of impeachment hearings.

Simpson and Fritsch are open about their desire to push back on the years of criticism they and Steele have faced. “Crime in Progress” provides a detailed account of how Fusion GPS began its work researching then-candidate Trump — the project, they remind readers, was originally funded by the conservative Washington Free Beacon — and then, after Steele’s reports from Moscow began to roll in, how the three men scrambled to alert both the press and the FBI to the astonishing information they’d uncovered. They had no intention that the dossier would ever become public. And contrary to suggestions by the president’s allies, they played no role in the opening of the FBI’s investigation into Russian election interference.

“Crime in Progress” is most interesting as an addition to the burgeoning genre of journalism about journalism — media that, in a truth-starved time, seeks to explain not only the reporter’s conclusions but also how the reporter arrived at them. Simpson and Fritsch walk through the mechanics of conducting the investigation that arrived at such incendiary results and, in telling of how murmurs of the dossier circulated through Washington, provide a case study in how information travels among journalists, politicians and hired guns.

The catch is that Simpson and Fritsch fall into the latter category, not the former. They left behind work as reporters for the Wall Street Journal to found Fusion, which Simpson described in 2016 as “journalism for rent” — a notion that journalists tend to find somewhat disreputable. But whether or not one approves of Fusion as an enterprise, Simpson and Fritsch’s efforts to justify some of their ­less-savory work begin to drag the story down. In particular, the two are defensive about their hiring by the Russian company Prevezon, which sought their help in fighting a U.S. government lawsuit over alleged fraud and money laundering. It’s difficult to square this with Simpson and Fritsch’s descriptions of the danger they think Russian meddling posed to the American republic.

If Simpson and Fritsch are journalists for rent, Steele was a spy for rent: He founded his research firm after leaving his role as a Russia expert at the British intelligence agency MI6. And just as “Crime in Progress” is a primer in the undercurrents of information swirling through Washington, it also seeks to explain the work of intelligence-gathering. Contrary to suggestions by the president and his defenders, the dossier was never intended to be a completely accurate account of links between Trump and the Kremlin: “In intelligence, as journalism,” Simpson and Fritsch write, “all sources merely pass along what they see, hear, or think — not all of which turns out to be correct.” Steele, they say, “remains confident that at least 70 percent of the assertions in the dossier are accurate.”

But which 70 percent? In the years since the dossier’s publication, any number of reporters and analysts have sought to untangle this question, with little success. Without vouching for the accuracy of every sentence, Simpson and Fritsch do their best to make the case for the document’s reliability. The dossier, they argue, “offered a set of findings that provided insights into Trump’s persistent adulation for a regime in Moscow that has sought to undermine U.S. goals around the world since [President Vladimir] Putin took office in 1999.” Yet they are frustratingly coy about some of the dossier’s more controversial claims. On the supposed lewd tape of Trump in Moscow — which has, years later, yet to surface or be corroborated by any reporting — they suggest, “The answer still isn’t known, but some evidence supports the possibility.” Or take the dossier’s assertion that Trump’s lawyer Michael Cohen met with Russians in Prague in 2016, which Cohen has disputed and which the Mueller report dispatches with quickly. Yet Simpson and Fritsch insist that “the facts . . . remain frustratingly beyond reach.”

They, and Steele, suggest that those who argue that the dossier might contain disinformation seeded by the Russian intelligence apparatus simply don’t know what they’re talking about. But among those who have raised concerns along these lines is Russia expert Fiona Hill, the former National Security Council official who testified to great fanfare in the impeachment inquiry. The dossier, Hill warned, was a “rabbit hole” of potential disinformation.

This may be the biggest debate between the Fusion team and its many critics: Is the dossier a rabbit hole or a document of profound significance? Many Republicans argue, falsely, that Steele’s work was used to kick-start the FBI’s Russia probe and therefore the whole probe was tainted from the start. Simpson and Fritsch are right to dispute this. But they take credit for “trigger[ing] a cascade of events that disrupted a secret rapprochement brewing between the incoming Trump administration and the Kremlin” — and ultimately led to the Mueller investigation. This seems overstated, given that the FBI’s work on Russia began independently of Steele and that Trump would probably have clashed with then-FBI director James Comey, leading to Comey’s dismissal and Robert Mueller’s appointment as special counsel, even in the dossier’s absence.

The strangeness of the Steele dossier as a political artifact is that, in the storm of the Mueller report and the ongoing Ukraine scandal, its significance has largely faded outside the circle of Trump’s most ardent supporters. In “Crime in Progress,” Simpson and Fritsch do their best, not always convincingly, to renew the case for its overarching importance. For all the bad blood between the authors and the president’s defenders, both sides have ended up arguing that the document played a crucial role in the events of the past few years. On this, at least, they agree.

Crime in Progress

Inside the Steele Dossier and the Fusion GPS Investigation of Donald Trump

By Glenn Simpson and Peter Fritsch

Random House. 346 pp. $30