When Bill Daley became Barack Obama’s chief of staff, he immediately called James Baker, widely regarded as the gold standard for the role. Daley’s version of the conversation: “Congratulations,” Baker told him. “You have the worst blanking job in America.” (We’re guessing Baker didn’t say “blanking.”)

From left to right, Former White House Chiefs of Staff Josh Bolten, Jim Jones, Jack Watson, John Sununu and Ken Duberstein at the launch party Tuesday night. (Nick Wass/AP Images for Discovery Channel)

Ah, but what a job: The president’s closest adviser, truth-teller, confidant, consigliere, pinata — and now the subject of a four-hour documentary, “The Presidents’ Gatekeepers,” debuting Wednesday and Thursday on the Discovery Channel.

The film boasts extensive interviews with all 20 living chiefs-of-staff and five — Josh Bolten, John Sununu, Jack Watson, Ken Duberstein, and Jim Jones — attended Tuesday’s launch party at the Mellon Auditorium.

“Most people walk into the Oval Office and tell the president what they think he wants to know,” Duberstein, Reagan’s last COS, told us. “Your job is to tell him what he needs to know.”

To a man, they all said it’s a brutal position with grueling hours, massive responsibilities and no breaks (the average chief-of-staff lasts less than two years) and to a man, they said they’d do it again. So they’ve developed into a bipartisan fraternity — we saw lots of back-slapping and exchanging business cards.

“It’s a great job,” said Sununu, who served three years for George H. W. Bush. “I loved it.” Best part? Helping the boss making the tough calls: “The best presidents are the ones that are willing to make the decisions and the worst presidents are the ones who always figure out ways to avoid the decisions.”

Not that he was naming names, although the screening fell just a couple hours before Obama’s speech on Syria. What’s a night like that like for a chief-of-staff?

Calm, at least in the Bush 43 White House, said Bolten. “We’d have it buttoned down, he’d have practiced it and we’d be trying to relax a bit.” Bolten said he’d hang out with Bush or review pre and post-speech media plans. (In other words, spin?) “Absolutely,” he said. “But honest spin.”

Pelosi with Discovery Channel's David Leavy, (left) and David Zaslav. (Charlie Archambault) Pelosi with Discovery’s David Leavy, (left) and David Zaslav. (Charlie Archambault)

Guests at the party, bouncing from multiple political events Tuesday night, including Democrat Leader Nancy Pelosi, former Sen. Chuck Robb, lobbyists Jack Quinn and Heather Podesta, and superlaywer Bob Barnett. Most stayed for the president’s speech, thanks to a late buffet dinner that appeared just before address.

In case you’re wondering: A short version of the documentary was screened at the White House this summer. The president briefly dropped in but left before the film started: His chief-of-staff told Obama he couldn’t stay.

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