Donald Trump has said that he is “100 percent” willing to be interviewed by Robert Mueller. The president’s top defense lawyer in the Russia investigation, Ty Cobb, is singing a similarly cooperative song, saying the president is “very eager” to sit down with the special counsel. We’ll see if Trump actually follows through, raises his right hand, and testifies. But the preparations for a Trump-Mueller showdown are well underway, on both sides of the probe—and the presidential posturing is a key part of the negotiation.

Inside Mueller’s office, at an undisclosed location in southwest Washington, his team of 17 lawyers is no doubt assembling a list of possible questions for Trump, and combing through Trump’s many previous depositions for clues as to how he handles an interrogation. “The superficial view would be that every day this guy makes stuff up as he goes along, so Trump is going to be a terrible witness, and he’ll say things that will get him in trouble,” says Sam Buell, a former federal prosecutor who was part of the government’s team in the Enron case. “But Trump has experience as a litigant, and maybe he understands the game. So, in his prior depositions, you’re looking for the style in which he answers—the extent to which he’s prepped.”

That history is voluminous and decidedly mixed. Trump, in a 2012 deposition for a lawsuit against Trump University, testified that he’d been a witness “over 100” times. Often he seems nonchalant: In a 2016 dispute over celebrity chef Geoffrey Zakarian’s deal to open a restaurant inside Washington’s Old Post Office, Trump claimed he’d done “virtually nothing” in preparation for questioning. Sometimes he is both conversant in fine details and craftily evasive. Trump sued journalist Tim O’Brien, claiming the journalist had understated Trump’s net worth. O’Brien’s attorneys, in a 2007 deposition, caught Trump in a series of falsehoods and exaggerations. “My net worth fluctuates, and it goes up and down with markets and with attitudes and with feelings, even my own feelings,” Trump said. “I try and be truthful. I’m no different from a politician running for office. You always want to put the best foot forward.” A judge dismissed the lawsuit.

There is also, infamously, the 2011 deposition during which Trump erupted in anger when attorney Elizabeth Beck, who had recently given birth, said she would use part of the lunch break to pump breast milk. “He starts screaming, ‘You’re disgusting!’” Beck says. “Maybe Mueller should wave a breast pump in front of Trump.”

Not likely. Mueller himself is resolutely no-nonsense, as is Andrew Weissmann, who seems likely to lead any questioning of Trump. “Andrew is super-thorough, persistent, and factual,” says Buell, who worked with Weissmann on the Enron case. “He’ll know the record cold, and he’ll be a good listener, to see if he really gets an answer to the question he’s asked. He’s not going to get excited. It will be interesting if he drills down on the different statements and tweets with regard to the [James] Comey firing, or Russia: ‘So, when you wrote this on Twitter, was that a statement of fact? Did you believe it to be true?’”

Roughly two miles to the north of Mueller’s quarters, Cobb—with the help of colleagues including John Dowd and Jay Sekulow—is compiling the counter-intelligence. Central to that effort has been sharing notes with lawyers for people who have already been quizzed by Mueller—current staffers like Hope Hicks and Jared Kushner, former aides like Paul Manafort, and, before he pled guilty to lying to the F.B.I. and began cooperating with the investigation, former national security adviser Michael Flynn. “Joint defense agreements can get very tricky,” a prominent white-collar defense lawyer says. “Because at some point, the clients’ self-interests can start to conflict.”