Their premise is straightforward. After multiple bankruptcies in 1990s and 2000s, Trump was unable to find conventional financing for projects. He almost entirely abandoned real estate development and, instead, licensed his name to anyone willing to pay a price.
Yet on nearly every project, Trump partnered with extremely dubious individuals, all of whom were either directly or indirectly involved in money laundering and/or other illegal activities. Of the direct development in which Trump was still involved, many of the buyers were foreign nationals, particularly Russians, who bought with shell companies.
If you go down the list of all of Trump's projects in the last two decades, virtually every single one involves at least one partner with some kind of suspicious history. As the Fritsch/Simpson piece notes, a business can't just look the other way when conducting business with dodgy people; federal law requires due diligence, which it does not appear Trump and company every much conducted.
These are inconvenient truths for Trump's dwindling number of supporters and Republicans in Congress who still back the President.
For the nation, above and beyond the issue of having an extremely dodgy businessman in the Oval Office, Trump's many shady business partners put the country at risk. Trump could easily be blackmailed about one or several of these projects -- and may already have been done so -- and he could also make decisions as President for the benefit of his own businesses and partners and not the country. There is considerble evidence to suggest that has already happened.
Hopefully, Special Counsel Robert Mueller and his team are examining these matters as part of the criminal investigation into Trump, and there are signs they have been doing so. As well, the US Attorney for the Southern District of New York may also be examining these matters as part of their investigation into Michael Cohen, Trump's lawyer/fixer who is likely to be charged in the near future with a number of crimes.
If Congress had any sense of responsibility, they would also be investigating these matters and holding public hearings. Unfortunately, until Republicans lose control of at least one chamber of that body, no investigation will be forthcoming.
That's why it's so important that everyone who is not registered to vote does so and votes this November. Matters this grave cannot be ignored much longer.