Presidential candidate Donald Trump, right, gestures at Sen. Ted Cruz (Tex.), center, and former Florida governor Jeb Bush during theGOP primary debate in Greenville, S.C., on Feb. 13, 2016. (Spencer Platt/Getty Images)

Hillary Clinton is methodically preparing for the presidential debates as a veteran lawyer would approach her biggest trial. She pores over briefing books thick with policy arcana and opposition research. She internalizes tips from the most seasoned debate coaches in her party. And she rehearses, over and over again, to perfect the pacing and substance of her presentation.

Donald Trump is taking a different approach. He summons his informal band of counselors — including former New York mayor Rudolph W. Giuliani, talk-radio host Laura Ingraham and ousted Fox News Channel chairman Roger Ailes — to his New Jersey golf course for Sunday chats. Over bacon cheeseburgers, hot dogs and glasses of Coca-Cola, they test out zingers and chew over ways to refine the Republican nominee’s pitch.

Trump’s aides have put together briefing books, not that the candidate is devoting much time to reading them. Trump is not holding any mock debates, proudly boasting that a performer with his talents does not need that sort of prepping. Should Trump submit to traditional rehearsals, some associates are talking about casting Ingraham, an adversarial chronicler of Clinton scandals, to play the Democratic nominee.

“Donald Trump is the unpredictable X-factor and Hillary Clinton is the scripted statist,” said Kellyanne Conway, Trump’s new campaign manager, in an interview. “I fully understand why Team Clinton feels the need to drown her in briefing books and Hollywood consulting.”

Amid a combative period of campaigning, during which each has flung ferocious accusations, Clinton and Trump are also taking time to warm up for their biggest showdowns. The first of three presidential debates, on Sept. 26, promises to be one of the highest-rated television events of the year, the first opportunity for voters to evaluate the candidates side by side and one of the last moments for either to alter the trajectory of the race.

Clinton’s advisers are confident the debates will showcase her experience, judgment, gravitas and command of policy.

“She feels like it is a proving ground, that this is a job interview,” Clinton spokesman Brian Fallon said. “I think she will approach the debate with a great deal of seriousness and a sense of purpose, and also keenly aware that Donald Trump is capable of anything.”

The forum brings considerable challenges. Clinton must not only parry what her campaign expects will be a stream of insults and innuendo from Trump, but she also must overcome the perception among many voters that she is not trustworthy.

“People think that they have to land zingers and pivot and attack — and that’s true, but ultimately, you want your viewers to come away with a gut feeling that I like this person,” said former Michigan governor Jennifer Granholm, who co-chairs Clinton’s transition committee.

For Trump, who trails Clinton in nearly all national and battleground-state polls, the debates represent perhaps his best opportunity to change perceptions.

The outsider candidate needs to convince voters he is up for the job. Known for an unpredictable and, at times, erratic temperament, Trump must prove that he can be a steady commander in chief, with an understanding of the issues. And after more than a year of making damaging comments about women and minorities, he will try to use the big debate stage to show that he would be an inclusive president.

Trump, along with Paul Manafort, Reince Priebus, and Jeff Sessions, faced questions Sunday about possible changes to the debate schedule which was set by an independent commission in 2015. (The Washington Post)

“You’re going to see a very natural and normal guy — someone who is comfortable with who he is, not someone who’s highly scripted or nervous,” Giuliani said. “The real risk is when a guy tries to be something other than what he is.”

The first debate, at Hofstra University just outside New York City, will be rife with personal drama. Clinton and Trump are two of the most prominent personalities in a city filled with them. They once had a chummy rapport — Clinton and former president Bill Clinton famously attended Trump’s 2005 wedding to Melania — but they have spent the summer scolding each other in increasingly incendiary language.

During the Republican primary, Trump bragged about taking on Clinton and has eagerly anticipated debating her since even before entering the race, according to his associates.

“Not only does he want 100 million viewers, he wants to be a showstopper at the Roman Colosseum, the main event at WrestleMania,” said Sam Nunberg, a former adviser who helped the billionaire chart his White House run. “He’s going to love this, eat it up and take her on. For Hillary to go in and think she’ll be professional and wonky, or give a long lecture, that’ll play against her.”

Political campaigns often play the expectations game, and Clinton’s aides are trying to raise the bar for Trump. They insist that his years on reality television and his pugnacity and agility in the Republican primary debates make him a fearsome adversary.

“We are fully expecting to have our hands full,” Fallon said. “It was his television personality that carried the day and made him a success at the [primary] debates. What normally would make for low expectations in terms of a lack of substance and not sort of exuding that commander-in-chief demeanor has actually been turned on its head.”

The debates are run by the nonpartisan Commission on Presidential Debates, which long ago picked the dates and locations: The second is Oct. 9 at Washington University in St. Louis and the third is Oct. 19 at the University of Nevada at Las Vegas. The commission also hosts one vice-presidential debate, Oct. 4 at Longwood University in Farmville, Va.

To participate, the commission requires that candidates average at least 15 percent in national polls, a threshold neither Libertarian Party nominee Gary Johnson nor Green Party nominee Jill Stein yet meets.

The commission dictates the format and selects the moderators, who are expected to be named soon after Labor Day. Traditionally, the first debate is on domestic policy, the second is a town hall with audience questions and the third is on foreign policy, with the debates divided by subject into 15-minute sections.

So far, only Clinton has officially agreed to appear. Trump has vowed to negotiate for more favorable terms, saying in a recent interview with The Washington Post that he would try to influence the selection of moderators: “I’d want to have a fair moderator.”

The campaigns are allotted no official input, although the commission historically has accommodated some requests, such as whether candidates sit around a table or stand behind lecterns.

One potential hiccup: Each debate runs for 90 minutes, with no breaks. In the primary debates, Trump and Clinton both took advantage of frequent commercial breaks to use the restroom or collect their thoughts.

Trump had been represented with the debate commission by campaign chairman Paul Manafort, but he recently resigned under pressure. Giuliani has stepped into that role, along with campaign lawyer Donald F. McGahn.

Unlike Clinton, Trump has no official debate team. His strategy is being shaped by an assortment of advisers, family members and friends, some of whom Trump gathered last Sunday at the Trump National Golf Club in Bedminster, N.J., to strategize with him as he read print-outs of news articles and monitored television news. They plan to reconvene at Bedminster this Sunday.

Present were Conway and newly hired campaign chief executive Stephen Bannon, as well as communications adviser Jason Miller. They were joined by Ailes and Giuliani, both longtime friends of Trump’s; Ingraham, who is close to Conway and admired by Trump for her cutting Clinton commentary; and Trump’s daughter Ivanka and her husband, Jared Kushner, according to people familiar with the meeting, who spoke on the condition of anonymity because the talks were private.

They said Ailes shared war stories from campaigns past and insights into the more cinematic elements of politics. The former Fox chief engulfed in a sexual-harassment scandal has been in regular touch with Trump by phone, dispensing advice about television advertisements, speech lines and Clinton attacks.

Conway said of Trump: “He’s an unconventional candidate, so debate prep in the classic sense doesn’t apply to him. That applies to the accoutrements that are usually associated with getting ready for debates: contrived gestures, lecterns, a group of consultants in belted khakis holed up in a cabin, the Socratic method of peppering questions. That’s not him.”

Retired Army generals Michael Flynn and Joseph “Keith” Kellogg have been tutoring Trump on national security, and New Jersey Gov. Chris Christie, who chairs Trump’s transition project, helps in a variety of areas. Campaign policy adviser Stephen Miller has been assembling Trump’s briefing materials.

On the periphery is David N. Bossie, president of conservative group Citizens United, who has made a career of investigating the Clintons. Trump also seeks out Roger Stone, a controversial bon vivant and self-proclaimed political dirty-trickster, who has advised Trump for decades but no longer works for him.

Asked about Trump’s debate strategy, Stone said: “I don’t believe in telegraphing one’s punches. I don’t want to tell the Clintonites.”

So far, Trump has been heavily influenced by flame-throwing Clinton critics, but campaign officials are considering inviting more mainstream Republicans to join the discussions, such as military figures and members of Congress, believing Trump would benefit from a diversity of perspectives.

Brett O’Donnell, regarded as one of the GOP’s best debate coaches, said that when Manafort was still chairman of the Trump campaign, he asked whether O’Donnell would assist their candidate, but those talks quickly dissolved. O’Donnell said Trump should be preparing rigorously.

“He thinks he won all the primary debates,” O’Donnell said. “But he picked his spots, beat up on a candidate and then evaporated for a while and stayed out of the substance. He’s not going to be able to hide like that with just the two of them on stage. . . . He can’t just name-call her and have a wrestling match for 90 minutes.”

Republican lawyer Benjamin Ginsberg, a veteran presidential debate adviser, said: “There ain’t no lifelines. You can’t ask an adviser what they think, you can’t read off a prompter, and you have to talk far more in-depth about any given subject than you had to in any primary debate.”

Facing off against a female candidate is an additional dimension. Communications experts said Trump risks appearing like a bully, noting that one of Trump’s worst moments in the primary debates was when Carly Fiorina shamed him for his comments about her looks.

“Odds are any name-calling backfires,” said David Brock, who runs a conglomeration of pro-Clinton super PACs. “Any false insinuation that Hillary is old and frail will be countered right on stage with her presence, which conveys the opposite.”

Clinton’s debate negotiations are led by operative Ronald Klain, who is so steeped in presidential debates that he teaches a course on the subject at Georgetown University, and Washington lawyer Karen Dunn. The two prepare briefing materials and run the practice sessions. Longtime policy adviser Jake Sullivan helps run the sessions as an adviser without portfolio. Veteran Clinton lawyer Robert Barnett, media advisers Mandy Grunwald and Jim Margolis, campaign chairman John Podesta, strategist Joel Benenson, and communications director Jennifer Palmieri often attend or weigh in.

Clinton aides have not revealed who is standing in for Trump, and they said it is possible that multiple people could play the role.

Clinton has built considerable downtime into her calendar recently, but her aides refused to detail her debate-related activities. Fallon said only: “She does her homework.”

Clinton is most comfortable when she is hyper-prepared, but some of her friends have suggested she study less, arguing that memorizing policy minutiae is less important than extemporaneously shadowboxing Trump, according to two Democrats who have known the candidate for years.

Clinton has countered that her marathon prep sessions last fall for her 11-hour testimony before a congressional panel on the attacks in Benghazi, Libya — going over lines of questioning from multiple angles, testing how lawmakers might try to trip her up — paid dividends.

Clinton’s allies said it is essential that she be ready to stymie any attempt by Trump to come across as sober and serious.

“The man has the thinnest skin that we’ve ever seen, so getting a reaction out of him and pulling the now well-known Trump personality out will be important,” said strategist Stephanie Cutter, a veteran of President Obama’s campaigns.

Clinton’s advice is not coming only from political professionals. On the fundraising circuit this month — from Nantucket, Mass., to Beverly Hills, Calif. — donors have peppered her with tips for how to knock out Trump.

“I don’t think there’s a person who gets on that grip-and-grin line who doesn’t offer advice,” said Ken Solomon, president of the Tennis Channel and the Democratic National Committee’s finance vice chairman. “It could be the popcorn event of the year.”

Matea Gold contributed to this report.