This story appears in the December 2016 issue of Playboy. Subscribe

This week, all the world is watching as Donald Trump comes to grips with what it means to transition into the most powerful man on the planet. While the presidential campaign was still underway, political correspondent John Meroney reported how this process unfolds. Here’s his story, which appears in the December 2016 issue, on stands now.

For a new president, no time is more fraught with peril than the period between Election Day and the swearing-in ceremony on January 20. This so-called transition period costs about $40 million and amounts to the biggest power grab in the world. More important, how the president-elect plays this interval will determine whether the next four years are a triumph or a disaster.

“Presidential campaigns are like an MRI for the soul—whoever you are, eventually people will find out.” That’s the famous line Barack Obama’s chief strategist, David Axelrod, uses to describe the long national nightmare we’ve just endured. But the first few days post-election and how our new president spends them are just as revealing.

The groundwork began in earnest this summer when Hillary Clinton and Donald Trump established their transition offices in Washington, D.C. The incoming president must fill about 8,000 jobs and so must be ready to put operations into overdrive the morning after Election Day. It’s a painstaking process: The FBI performs background checks on all new employees, and 800 of them will have to undergo U.S. Senate approval. “The FBI checks are quick if you have no financial holdings, you have never traveled and you have lived in the same place for 30 years,” said an aide who worked for President George W. Bush in a New York Times interview. No wonder many presidential appointees will still be running the gauntlet in August.

“Bill Clinton would ask for more names, saying the lists didn’t have enough people of stature or anyone who’d helped get him elected,” says political journalist and author Elizabeth Drew, who covered the first few years of his presidency.

When Clinton tried to fast-track the nomination of Zoë Baird for attorney general, his team didn’t perform enough due diligence and was embarrassed when it was revealed that Baird had employed an illegal immigrant as a nanny. This erupted into one of those minor Washington scandals that won’t go away. Clinton was forced to rescind Baird’s nomination and start over, costing his presidency valuable time.

The other risk for the president-elect is disloyal new employees. Jimmy Carter won the White House as an outsider campaigning against the establishment, including members of his own Democratic Party. But there weren’t enough qualified outsiders to join him in office, so he hired party hacks—many of whom hated him. In three years, they turned on an embattled Carter and massed around Senator Ted Kennedy, who challenged him for renomination. “If Kennedy runs, I’ll whip his ass,” Carter said, and though he did just that, the internal party opposition wounded Carter and contributed to his failure to win reelection.

The most successful presidents come into office with a clear legislative agenda. Ronald Reagan focused on turning around an economy that was in recession, even pushing his budget and tax policies through Congress while recovering from an assassination attempt. Before summer ended, he’d made a deal with Congress that he signed into law. When Reagan was reelected in 1984, he won in a landslide of 525 electoral votes.

Advisors to Bill Clinton still comment on how he just couldn’t stop campaigning after his first election—from talking to volleyball players in Santa Barbara to greeting 30,000 shoppers at a Los Angeles–area mall. By the time he took office, he was overwhelmed. “It was totally chaotic,” says one of his transition staffers. It didn’t help that Clinton’s agenda was a hodgepodge—gays in the military, health care overhaul, economic policies. The Republicans exploited his lack of focus and in two years won back control of Congress, creating a GOP opposition that spiraled for the rest of Clinton’s presidency and continues today.

Perhaps most important is knowing how to “work the levers of power in Washington,” says commentator Chris Matthews. He was a speechwriter for Carter and then worked for Democratic House Speaker Tip O’Neill during the Reagan presidency. Reagan was a master at getting cozy with Congress in his first term, something Obama ignored. “Reagan was fond of O’Neill’s motto that political battles ended at six o’clock,” Matthews says. “When he would call O’Neill, Reagan would say, ‘Hello, Tip, is it after six?’”

President John F. Kennedy’s speechwriter Ted Sorensen once said that in those early days of a new administration, failure is unthinkable. “In the heady atmosphere of infallibility that follows successful campaigns, it is hard not to be impressed by the secret maps, arcane terminology, gold braids and experts’ crisp, confident manner,” he wrote. “Success is in the air”—and after surviving the arduous adventure of getting elected, that’s exactly when some of the greatest presidential campaigners have faltered as presidents.