As the deal takes shape in 2017, Mr. Bobulinski begins to question what Hunter will contribute besides his name, and worries that he was “kicked out of US Navy for cocaine use.” Mr. Gilliar acknowledges “skill sets [sic] missing” and observes that Hunter “has a few demons.” He explains that “in brand [Hunter is] imperative but right know [sic] he’s not essential for adding input.” Mr. Bobulinski writes that he appreciates “the name/leverage being used” but thinks the economic “upside” should go to the team doing the actual work. Mr. Gilliar reminds him that those on the Chinese side “are intelligence so they understand the value added.”

This dispute almost derails the deal. Hunter is hardly visible through most of the work, until final contract negotiations ramp up in mid-May. He brings in his uncle Jim Biden for a stake. (Mr. Gilliar in a text message soothes Mr. Bobulinski with a promise that Jim’s addition “strengthens our USP”—unique selling proposition—“to the Chinese as it looks like a truly family business.”) Hunter in texts and emails wants offices in three U.S. cities, “significant” travel budgets, a stipend for Jim Biden, a job for an assistant, and more-frequent distributions of any gains. As for annual pay, he explains in an email that he expects “a hell of a lot more than 850” thousand dollars a year (the amount Mr. Bobulinski, the CEO, is getting), since his ex-wife will take nearly all of it.

Mr. Bobulinksi pushes back, warning Mr. Gilliar in a text that they need to “manage” Hunter because “he thinks things are going to be his personal piggybank.” The duo worry about his “mental state,” substance abuse, and his ability to make meetings.

Hunter, in his own angry texts, makes clear that his contribution is his name. He rails at Mr. Bobulinski that the CEFC heads are “coming to be MY partner to be partners with the Bidens.” He reminds him “that in this instance only one player holds the trump card and that’s me. May not be fair but it’s the reality because I’m the only one putting an entire family legacy on the line.” Mr. Gilliar privately tells Mr. Bobulinski to show flexibility, since “I know why [CEFC Chairman Ye Jianming] wants the deal and what makes it enormous, It’s the family name.”

CEFC was closely entwined with the Chinese government and military until it went bankrupt, following U.S. charges of money laundering. There is no question CEFC was buying Hunter for influence.

Joe Biden claims he has never discussed his son’s business. Yet a May 2017 “expectations” document shows Hunter receiving 20% of the equity in the venture and holding another 10% for “the big guy”—who Mr. Bobulinski attests is Joe Biden.

In one text, Hunter says that “my Chairman gave an emphatic NO” to a version of the deal. Mr. Walker, Hunter’s partner, explains in a text to Mr. Bobulinski that when Hunter “said his chairman he was talking about his dad.”

Mr. Bobulinski’s texts show he even met with Joe Biden. Mr. Gilliar reminds him in May 2017: “Don’t mention Joe being involved, it’s only when u are face to face, I know u know that but they are paranoid.” Mr. Biden had left office by then, though CEFC was always a suspicious company with ties to a rival government. It would have a been risky for any public figure to deal with it, much less a potential presidential candidate. Mr. Biden was given ample opportunity to deny the authenticity or facts of the Bobulinski information at Thursday’s debate; he didn’t.

The deal fell through on the Chinese end in the summer of 2017. CEFC was supposed to supply $10 million; it never arrived. This is where the Johnson report comes in. The Senate report notes that CEFC wired $5 million to a company called Hudson West in August 2017. The report says an associate of CEFC Chairman Ye in September opened a line of credit under Hudson West’s name, and Hunter, Jim Biden and Jim Biden’s wife, Sara, were given credit cards associated with the account, and bought items totaling more than $100,000.

The report says Hudson West also sent $4.7 million in “consulting fees” to Mr. Biden’s law firm over the course of a year. Mr. Bobulinski suspects Hunter and Jim had found an easier way to cash in on their name, one that didn’t involve pesky partners and complex deals. He sent a furious text to Jim Biden after the release of the Senate report, accusing Hunter and Jim of “lying” to their partners and secretly taking money from CEFC. The FBI last year subpoenaed Hunter’s laptop. A call to Hunter Biden’s attorney was not returned by our deadline.

All of this is news. The press corps that is ignoring it spent four years writing about Donald Trump’s Moscow business. The correspondence meanwhile blows up Rep. Adam Schiff’s claim that the Hunter story is Russian “disinformation.” It raises real concerns about what security risks Hunter might pose for a Biden administration. And it raises questions about Joe Biden’s involvement.

The former vice president is running on trust and good judgment. The Hunter tale is at best the story of a wayward son and indulgent father. At worst, it is an example of the entire Biden clan cashing in on its name with a U.S. rival. As Mr. Biden refuses to answer questions about this case, voters will have to make up their own minds. But given Hunter’s exploits in China, Ukraine, Kazakhstan and elsewhere, much more is yet to come—in the next week and a half and potentially in a Biden presidency.

Write to kim@wsj.com.