With the revelation by prosecutors on Wednesday that a tabloid publisher admitted to paying off a Playboy model, key participants in two hush-money schemes say the transactions were intended to protect Donald J. Trump’s campaign for president.
That leaves Mr. Trump in an increasingly isolated and legally precarious position, according to election law experts. Hundreds of thousands of dollars in payments made in 2016 to keep two women silent about alleged affairs are now firmly framed as illegal campaign contributions. The tabloid publisher, the parent company of The National Enquirer, said it had bought one of the women’s stories to ensure she “did not publicize damaging allegations about the candidate.”
Where the investigations go from here is not clear. The prevailing view at the Justice Department is that a sitting president cannot be indicted, though prosecutors in Manhattan could consider charging him after leaving office.
Investigators have continued to scrutinize what others in the Trump Organization may have known about the crimes described by Mr. Cohen, including its chief financial officer, according to people briefed on the matter. Prosecutors have met with campaign officials and asked how the campaign interacted with Mr. Trump’s company, which shared office space and employees.
Mr. Trump with Karen McDougal, a model who was paid by A.M.I. in exchange for her silence about an alleged affair.
Establishing a nexus between Mr. Cohen’s efforts to silence the women and Mr. Trump’s campaign is central to making a criminal case of election law violations. That is why A.M.I.’s admission carries so much weight, said Richard L. Hasen, an election law professor at the University of California, Irvine.
“It’s looking a lot like an illegal and unreported in-kind corporate contribution to help the campaign, exposing the Trump campaign and Trump himself to possible criminal liability,” Mr. Hasen said.
Until this week, it was largely Mr. Cohen’s word against the president’s denials. That is why the admission by A.M.I. is “highly significant, because it goes to corroborate” Mr. Cohen’s testimony, said Jeff Tsai, part of the prosecution team that accused Senator John Edwards of campaign finance violations when he arranged for payoffs to a pregnant mistress during his 2008 presidential campaign.
The Edwards case — which ended in an acquittal and mistrial — has been invoked by Trump allies as an example of prosecutorial overreach. Central to Mr. Edwards’s defense was that the payments were intended not to help his campaign but to hide the affair from his wife — that they were personal, not political.
The A.M.I. agreement with prosecutors said there was at least one other person associated with Mr. Trump’s campaign involved in an initial discussion in August 2015, attended by Mr. Cohen and Mr. Pecker, in which they agreed that the publisher would help the campaign by identifying negative stories about Mr. Trump’s relationships with women “so they could be purchased and their publication avoided.”
But many details remain hidden. Among them, the statement did not say whether the other campaign member was Mr. Trump himself — identified by prosecutors last week as attending a similar meeting — or some other person. A.M.I. had no comment on Wednesday.