The position of White House Chief of Staff may be the second-toughest job in the world.  It’s also the subject of a new documentary featuring insights from all 19 living former Chiefs.

Longtime ABC Newser Chris Whipple, now an independent producer, logged about 70 hours of interviews with members of this exclusive club for ”The Presidents’ Gatekeepers”. Viewers will hear from Chiefs ranging from Dick Cheney to Leon Panetta and Rahm Emanuel. Former presidents Jimmy Carter and George H.W. Bush also weigh in.

Before leaving network news about two years ago, Whipple spent nearly two decades at ABC, serving most recently as EP of the “What Would You Do?” series.  Earlier, Whipple was a CBS News producer with”60 Minutes”.

“Gatekeepers” runs four hours, and is scheduled to air in July on Discovery Channel.