Mr. Sater said it would be “pretty cool to get a USA President elected” and said he desired to be the ambassador to the Bahamas. “That my friend is the home run I want out of this,” he wrote.

Mr. Sater — a former F.B.I. informant who is famous for having once smashed a martini glass stem into another man’s face — has maintained a relationship with Mr. Cohen over the years. The two men have spent decades operating in the world of New York commercial real estate, where the sources of funding can be murky.

Through his lawyer, Mr. Sater declined on Monday to address why he thought the deal would be a political win for Mr. Trump. He said he brought the project to Mr. Cohen in late 2015, but that he was not working for the Trump Organization and “would not have been compensated” by them.

“During the course of our communications over several months, I routinely expressed my enthusiasm regarding what a tremendous opportunity this was for the Trump Organization,” Mr. Sater said.

Mr. Sater was a broker for the Trump Organization for several years, typically paid to deliver real estate deals. A company he worked for, Bayrock, played a role in financing the Trump SoHo Hotel in New York. Mr. Sater and Mr. Cohen even worked together on a peace plan for Ukraine and Russia that they sought to get in front of Mr. Trump’s national security adviser earlier this year.

As a broker for the Trump Organization, Mr. Sater had an incentive to overstate his business-making acumen. He presents himself in his emails as so influential in Russia that he helped arrange a 2006 trip that Mr. Trump’s daughter, Ivanka, took to Moscow.



“I arranged for Ivanka to sit in Putins private chair at his desk and office in the Kremlin,” he said.