President Trump jolted the White House yet again Friday when he announced that he was ousting embattled chief of staff Reince Priebus, instead bringing into the role Homeland Security Secretary John F. Kelly. Immediately, Washington insiders contrasted Priebus with Kelly, a retired four-star general and reported disciplinarian who “won't suffer idiots and fools.”

Still, Kelly faces a daunting job if he wants to succeed: to restore order to a White House that has been in turmoil since almost the very beginning of Trump's presidency. And while Kelly has a long history of enforcing order at high levels, there's an even longer history of White House chiefs of staff who have failed at their jobs, often because of circumstances outside of their control or lessons not learned early enough.

Chris Whipple knows this. The author of “The Gatekeepers: How the White House Chiefs of Staff Define Every Presidency,” Whipple spent five years interviewing 17 former White House chiefs of staff and researching the history of the position. He found that the job is critical to a “functioning White House” and, in turn, the success of the presidency. We spoke to Whipple about the challenges Kelly will face in his new role in the Trump administration — and the one thing that needs to happen for him to be able to turn the White House around.

First of all, can you summarize the turmoil in the White House now as it relates to the chief of staff — and did you foresee any of this as your book was nearing publication?

While the timing of the book was obviously impossible to forecast, it didn’t take a genius to figure out that Donald Trump was headed for trouble. I wrote an epilogue in December, before Trump took office. I essentially predicted that if Trump tried to run the White House the way he ran his campaign — based on seat-of-the-pants decisions without an empowered White House chief of staff — that it would be disastrous. This could not work. And that’s what we’ve seen over the last six months.

This White House is broken, perhaps beyond repair. It can’t do anything right. It can’t issue executive orders that are enforceable. It can’t pass legislation. It can’t prioritize the president’s agenda. It can’t get anybody on the same page. In a normal White House, all of those things flow from an empowered White House chief of staff who can execute the president’s agenda and most importantly tell him what he does not want to hear. And none of that is happening. ...