In the 1980s, Trump was concerned about nuclear proliferation and thought that he could do a better job negotiating a nuclear deal with the Soviets. In a 1984 Washington Post interview (which I believe you can see excerpts from in the film "Bully. Coward. Victim. The Story of Roy Cohn" about his mentor, Roy Cohn), he said:
"Some people have an ability to negotiate," he says. "It's an art you're basically born with. You either have it or you don't."
He would know what to ask the Russians for, he says. But he would rather not tip his hand publicly. "In the event anything happens with respect to me, I wouldn't want to make my opinions public," he says. "I'd rather keep those thoughts to myself or save them for whoever else is chosen . . .
"It's something that somebody should do that knows how to negotiate and not the kind of representatives that I have seen in the past."
He could learn about missiles, quickly, he says.
"It would take an hour-and-a-half to learn everything there is to learn about missiles . . . I think I know most of it anyway. You're talking about just getting updated on a situation . . . You know who really wants me to do this? Roy . . . I'd do it in a second."
Trump actually lobbied the George H. W. Bush administration to be the negotiator for arms talks, but the chief negotiator position went to Richard Burt, then U.S. Ambassador to West Germany, who later met Trump, and Trump explained what he would have done had he been the negotiator:
He explained that he would have welcomed—very warmly—the Soviet delegation. He would have made sure the country’s envoys were comfortable—very comfortable—at the table.
Then, Trump told Burt, he would have stood up, shouted “Fuck you!,” and left the room.
This seems quite likely -- and then he would have either given in to whatever the Soviets asked for, or failed to get a deal at all, which is what has happened again and again during his time as president. Where Trump gets deals it seems to be in spite of his own negotiations, rather than because of them.
When Trump gave in and signed the second COVID-19 stimulus bill which he had been refusing to sign and which was at risk of a pocket veto, one person who correctly predicted four days earlier that Trump would sign the bill was tax lawyer David Miller, who was someone who was actually on the other side of the table in a Trump negotiation over the Trump Organization's deal to purchase the General Motors building in 1998. Miller recounted the story in a thread on Twitter correctly predicting that Trump would sign the bill:
In 1998, I was the tax lawyer representing Conseco in a joint venture with the Trump Organization to buy the General Motors Building. 2/23
Conseco put up 99.9% of the capital, Trump put up 0.1% of the capital, and Lehman Brothers loaned the rest. 3/23
The joint venture agreement was very straightforward. Income and deductions were based on capital contributions. Everything was agreed quickly by the lawyers. 4/23
However, on the day before signing, we were told that Mr. Trump would be arriving at 10pm at our offices to negotiate the deal (which had already been negotiated). 5/23
He arrives with an entourage. A podium had been set up for him at the front of a long table in a conference room. 6/23
He asks for some minor corporate changes. But then he demands that he get all of the depreciation deductions. 7/23
Having negotiated, he put on his coat and left. 8/23
All of the lawyers look at each other. The general counsel of Conseco said, “We put up 99.9% of the money; we get 99.9% of the depreciation deductions.” Trump’s lawyers say, “Don’t worry, he’ll sign.” I go home to sleep. 9/23
The next morning my corporate partner and Trump’s corporate lawyer take the joint venture agreement to Trump Tower for Trump’s signature. I’m in my office. 10/23
The phone rings. It’s my corporate partner. “Mr. Trump wants to speak to you.” 11/23
“Yes, Mr. Trump,” I say. 12/23
“Were you there last night?” he asks. 13/23
“Yes, Mr. Trump, I was.” 14/23
“Did you hear me last night?” he asks. 15/23
“Yes, Mr. Trump, I did.” I reply. 16/23
“So, does this agreement give me the depreciation deductions?” he asks. 17/23
“No, Mr. Trump, it does not.” 18/23
He’s angry now. “You were there last night, you heard me, and this agreement does not give me the depreciation deductions? Why not?!” 19/23
I know that the agreement could have been structured for Trump to get depreciation deductions (if he was willing to provide a “bottom guarantee”). But it wasn’t, so I answer truthfully: “Mr. Trump, the law does not permit you to get depreciation deductions.” 20/23
He’s furious now. “The law does not permit me to get depreciation deductions?!” 21/23
“That’s right, Mr. Trump.” 22/23
He slams down the phone and signs the agreement. 23/23
Richard Burt's team successfully negotiated the START I Treaty, signed in 1991. Trump has withdrawn the U.S. from the Open Skies treaty for nuclear arms verification, and has so far declined the Russian offer to extend the New Start treaty, and has failed to negotiate a new nuclear arms treaty of any kind.