To readers who follow taxes and finance — subjects often introduced with the adjective “arcane” — David Cay Johnston is one of America’s best-known reporters. Johnston has worked on the staffs of Reuters, the Los Angeles Times, The Philadelphia Inquirer and from 1995 to 2008, The New York Times, where his writing on taxes won him a 2001 Pulitzer Prize. He’s branched out to other subjects too: His first book, published in 1992, was Temples of Chance: How America Inc. Bought Out Murder Inc. to Win Control of the Casino Business.

In a web post last July, Johnston asked 21 questions about Donald Trump’s finances. One pertained to Trump University, subsequently the object of close scrutiny in many venues. Others concerned mysteries about Trump’s charitable donations, his years paying zero income tax, his more recent — and undisclosed — tax returns and some his acquisition of casino licenses and his reputed connections with organized crime.

While there are some financial subjects on which the media has dared to grill the billionaire — ABC’s George Stephanopoulos last month got Trump to deliver a blunt “no” when he asked about the Republican nominee-apparent’s repeated refusal to release his recent tax returns, something every other recent presidential candidate has done — there has been remarkably little interest shown in some of Trump’s less-than-savory connections.

One of the exceptions is Johnston, who, over the course of 27 years, has had ample occasion to pay attention to Trump’s finances and mob ties. He was not the first investigative reporter to do so. In 1992, Johnston favorably reviewed the longtime Village Voice reporter Wayne Barrett’s highly unauthorized biography, Trump: The Deals and the Downfall, which, in Johnston’s words, “asserts that throughout his adult life, Donald Trump has done business with major organized-crime figures and performed favors for their associates.” As Barrett said not long after Trump declared for the presidency last year, Trump’s life “intertwines with the underworld.” Barrett updates his treatment of Trump in a new digital edition called Trump, The Greatest Show on Earth: The Deals, the Downfall, the Reinvention.

As Trump cements his leads atop the polls, questions about how he made his billions, and who helped him make them, are starting to take center stage.

Barrett’s quote appeared in a July 31, 2015, CNN online piece by investigative reporter Chris Frates, who added:

The allegations are getting new scrutiny as Trump runs for president, largely on his record as a successful and extraordinarily wealthy businessman. As Trump cements his leads atop the polls, questions about how he made his billions, and who helped him make them, are starting to take center stage.

While the story ran on CNN’s website, it never got any air time on the cable network. I tried to ask Frates why his investigation didn’t get onto TV, but didn’t hear back from him. In any event, nearly 11 months later, those questions about Trump’s financial life have still not reached that elusive center stage. The question is why.

Unlike its TV competitors, ABC News has raised some questions about Trump’s mob relations. Last December, a Good Morning America piece by the network’s investigative master Brian Ross touched on one tendril: Trump’s relationship with a twice-convicted felon, the Russian émigré Felix Sater, who (along with several other felons) occupied office space in Trump Tower. On air, Ross reported that Donald Trump had testified under oath in a civil lawsuit that Sater “helped develop the Trump SoHo hotel and condominium in New York City.” Online, in a simultaneous piece co-written with Matthew Mosk, Ross noted that in 1991, Sater got into an argument with a commodities broker at the bar of a New York restaurant, smashed a margarita glass and with the broken-off stem, slashed the man in the cheek and neck, breaking his cheek and jaw, severing nerves and lacerating his face and jaw. The victim required 110 stitches. Sater was convicted of first-degree assault and sent to prison in 1993. Then, in 2000, he pleaded guilty to federal racketeering charges for running a $40 million “pump and dump” stock scam and for, as Mosk and Ross wrote, “collaborating with members of four New York mob families.” Sater served no time, however, because the FBI testified at his sentencing hearing that he was “an important witness on both mob-related and national security matters.”

The BBC had pressed Trump on why he didn’t tell Sater ‘You’re fired!’ after reports surfaced alleging that the Trump associate had organized crime connections.

To date, Trump has danced away from straight answers about his former associates. In a 2013 video deposition for a civil lawsuit, Trump said: “If he [Sater] were sitting in the room right now, I really would not even know what he looked like.” This, Mosk and Ross noted, from a man who “touts his outstanding memory.” During the same deposition, “when asked about how much he knew about Sater’s past,” Mosk and Ross wrote, “Trump said he knew Sater had ‘got into trouble because he got into a barroom fight which a lot of people do.’” Trump added: “I don’t know him very well, but I don’t think he was connected to the Mafia.”

In his on-air piece, Ross pointed out that the BBC had pressed Trump on why he didn’t tell Sater “You’re fired!” after reports surfaced alleging that the Trump associate had organized crime connections. Trump rose from his chair mid-interview.“I hate to do this, but I do have that big group of people waiting so I have to leave,” he said. With that, he walked out of the room. “Trump later said under oath he did not remember being interviewed by the BBC,” Ross went on. In February, Trump’s then-rival Ted Cruz picked up the Trump-Sater story, but the issue died, at least temporarily, with Cruz’s campaign.

In April, The New York Times picked up the baton with a front-page investigation by Mike McIntire about Trump’s close collaboration with Felix Sater and other investors from the former Soviet Union. In McIntire’s words, “What sort of due diligence Mr. Trump did before jumping in with his new partners is unclear. But he, as well as many others, apparently missed some dark spots on Mr. Sater’s résumé.”

Beyond ABC News’ Ross, TV has been even less eager to press inquires about Trump’s history of relations with organized crime. Nor have questions of Trump’s mob ties been much explored in other major news outlets. A notable exception: Johnston, who, in Politico last month, raised yet more questions. One was why Trump relied on ready-mix reinforced concrete construction (mob-controlled) to build his eponymous Fifth Avenue tower and subsequent New York buildings, although steel girders were the usual choice. Another was why, when seeking a license to build casinos in Atlantic City, Trump received special treatment from New Jersey gaming investigators, “Thanks in part to the laxity of New Jersey gaming investigators,” Johnston wrote, “Trump has never had to address his dealings with mobsters and swindlers head-on.” Wayne Barrett calls Trump Tower “a monument to the mob.” He writes of the “sweetheart deals” that delivered the concrete, and the special tax abatements that have continued to roll in for Trump. There, so far as the public is concerned, the matter has rested. Why do the major media, ordinarily eager to fight for their own angles on big stories, lag? Why do the dogs not bark and the chambers not echo?

Trump’s financial dealings, by his own account, constitute his credential for the highest office in the land. They establish his proficiency at running a large organization, and therefore his ability to preside over the United States of America. That these dealings have not made a big story may partly be understood as a shortage of experienced newsroom eyes. Investigative reporting is labor-intensive. Skilled reporters have to be detached from everyday beats and set loose to follow trails that may, in the end, go nowhere. Newsroom buyouts and layoffs have made that harder to do. Experienced old hands are gone. Yet, even as advertising revenue has been slashed, newspaper profits remain at the 15- to 20-percent level. If coverage of Trump’s finances has been thin, that might well be because it’s too expensive — though the cost to democracy of not pursuing such obvious leads is a question that publishers might well be asking themselves.

One hypothesis, broached to me by an experienced reporter, is that news organizations fear Trump’s hair trigger when it comes to lawsuits. In the course of an April interview for his Politico piece, Trump bestowed one of his choice honors on Johnston: “if I don’t like what you write, I’ll sue you.”

“I’ll sue you” may yet become Trump’s second-most famous line, after “You’re fired.” The litigious Trump is indeed a sensitive fellow. He speaks frequently about “opening up the libel laws.” When pressed by the Washington Post editorial board to explain what he meant, in March, he disappeared into a haze of gobbledygook. But at least so far, it would seem that when it comes to journalists, his greatest sensitivity concerns his net worth. There, the defamation he worries about is to make him out to be smaller than he claims.

In 2006, Trump sued the financial reporter Timothy O’Brien — once Barrett’s research assistant — as well as the publisher of O’Brien’s book Trump Nation: The Art of Being the Donald, for understating Trump’s wealth. O’Brien wrote of what he called Trump’s “verbal billions.” O’Brien reported that three people close to Trump had estimated his worth at between $150 million and $250 million. Trump claimed to be worth between $4 billion and $6 billion, and maintained that O’Brien’s low estimate had hurt his reputation and cost him specific business deals. Foreshadowing his later outbursts against women who do not meet his standards, Trump told O’Brien: “You can go ahead and speak to guys who have 400-pound wives at home who are jealous of me, but the guys who really know me know I’m a great builder.”

But in 2009, a New Jersey judge threw out Trump’s suit, and in 2011, an appeals court sustained that decision. For, according to New York Times v. Sullivan, statements about public figures have to overleap a very high bar (or, in Trump parlance, wall), to be considered defamatory. They must be made with “actual malice” — that is, “with knowledge that [they are] false or with reckless disregard of whether [they are] false or not.”

So seriously, what do big news organizations, all outfitted with deep pockets, have to fear? One reporter I contacted notes that threats of lawsuits can chill investigations because, even in cases newspapers win, the legal bills can run into millions of dollars. Even deep pockets have limits. It’s also remotely conceivable that the TV networks, already aware of how juicy Trump has been for their bottom lines, are mindful of the possibility, however slim, that if he made his way to the White House he would appoint unfriendly members of the Federal Communications Commission — the officials who license the vastly profitable broadcast stations the networks own in the most lucrative markets.

I doubt it. But various reporters I’ve spoken with offer different explanations for the relative paucity of serious Trump investigations. Wayne Barrett thinks editors downplay Mafia stories because they think the subject is worn out: “The mob is so depleted,” he said. “Editors think it doesn’t feel real anymore. It feels historical.” Still, tabloids know that front pages mentioning mobsters sell papers. Another theory is that journalists are overwhelmed by the sheer profusion of Trump material. One major network news figure told me as much. A reporter with another major news organization said, “In one 24-hour news cycle there can be three different Trump story lines going. That sucks all the oxygen out of the room. It’s ADD on our part.” He added that TV stories needs pictures. But pictures of Trump with his erstwhile collaborators are not hard to come by, and surely there are more than enough news cycles left in the months to come. Indeed, this reporter tells me, “We have some things in the works.”

Reporters have collected dots, but it remains to connect them. As Walter Lippmann wrote, the mission of journalism is “to bring to light the hidden facts, to set them in relation with each other, and make a picture of reality on which men can act.”