No other candidate for the White House this year has anything close to Trump’s record of repeated social and business dealings with mobsters, swindlers, and other crooks. Professor Douglas Brinkley, a presidential historian, said the closest historical example would be President Warren G. Harding and Teapot Dome, a bribery and bid-rigging scandal in which the interior secretary went to prison. But even that has a key difference: Harding’s associates were corrupt but otherwise legitimate businessmen, not mobsters and drug dealers.

This is part of the Donald Trump story that few know. As Barrett wrote in his book, Trump didn’t just do business with mobbed-up concrete companies: he also probably met personally with Salerno at the townhouse of notorious New York fixer Roy Cohn, in a meeting recounted by a Cohn staffer who told Barrett she was present. This came at a time when other developers in New York were pleading with the FBI to free them of mob control of the concrete business.

From the public record and published accounts like that one, it’s possible to assemble a clear picture of what we do know. The picture shows that Trump’s career has benefited from a decades-long and largely successful effort to limit and deflect law enforcement investigations into his dealings with top mobsters, organized crime associates, labor fixers, corrupt union leaders, con artists and even a one-time drug trafficker whom Trump retained as the head of his personal helicopter service.