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The roll call vote watched by millions of Americans that cemented Donald Trump’s nomination took nearly two months of painstaking groundwork. And perhaps no one short of a certain businessman watching from New York was more relieved when it was over than the Georgian who is Trump’s chief delegate wrangler.

As Trump’s national delegate director, Brian Jack led the team responsible for recruiting and electing pro-Trump delegates, one by one, to reach the 1,237 mark that Trump needed to secure the nomination — and stave off a floor flight this week from die-hard supporters of Texas U.S. Sen. Ted Cruz and others who wanted to dump Trump.

Jack’s line of work usually goes unnoticed by the public. But in this election, with anti-Trump forces challenging the candidate at every turn, it morphed into one of the campaign’s most important roles.

During the spring, Jack traveled to nearly a dozen state and district conventions, spending the weekdays preparing for each session and the weekends on site trying to quell rebellions.

He borrowed tactics from Paul Manafort, the campaign’s chairman, who managed the floor fight that delivered the nomination in 1976 to Gerald Ford.

Jack and his colleagues made countless phone calls and personal visits to delegates who backed Cruz or other rivals. And through it all, he was counting, always counting: Trump delegates, committee votes, convention supporters.

“Knowledge and communication are key on a convention floor,” Jack said, “and our intelligence was informed through one-on-one communication, not by robocalls or internet surveys.”

Worked first for Carson

A sixth-generation Georgian who graduated from Woodward Academy, Jack worked as a data specialist for the Republican National Committee and political analyst for the pro-Israel lobby AIPAC before he joined Ben Carson’s campaign last year.

His role was to place the retired neurosurgeon on every state’s ballot in the primaries and then line up delegates for him to prepare for the convention. Meeting each state’s complicated requirements can be a mini-saga on its own.

Ohio, for instance, requires campaigns to line up 126 delegates who meet certain gender requirements to get on the state’s ballot. Just 16 days before the paperwork’s December due date, Carson’s campaign hadn’t locked down a single one. By deadline, though, they had turned in a full slate — and more than 500 pages of paperwork — to make the cut.

“If you qualify for every ballot, you get a pat on the back,” he said of the work. “But if you miss just one, it’s a major embarrassment for the campaign — and it’s all on you.”

Carson suspended his campaign in early March after dismal showings in primary states, and less than a week later, Jack had landed in Trump’s camp with the task of wrangling delegates. It was his team that secured enough uncommitted delegates to seal the nomination in late May — days before the June votes that were initially expected to put him over the top.

Jack’s role soon shifted to internal battles at the Republican National Convention. He was put in charge of building and managing the delegate whip operation for the platform and rules committees — the two panels where anti-Trump forces were making a final stand.

He worked with other Georgians — the campaign’s state Co-Chairwoman Rayna Casey on the platform committee, Republican National Committeeman Randy Evans on the rules committee and state director Brandon Phillips on the credentials committee — as Trump’s allies joined forces with party stalwarts last week to block the late push.

Organization staved off challenges

Chaos briefly erupted Monday when a group tried to force a vote that could have freed the convention’s 2,472 delegates to “vote their conscience” — and thus potentially jeopardize Trump’s nomination — but it was swiftly put down on live TV. Trump whips wearing neon green hats flooded the floor as a handful of the candidate’s angry critics stormed off.

“We trusted the system that we built,” Jack said. “We had something they didn’t — organization — and it worked.”

The final major test of the convention operation came Tuesday when each state’s delegation trumpeted its vote for president. It was the last chance for anti-Trump delegates to embarrass the candidate. But with some last-minute maneuvering, the Pennsylvania delegation deferred to New York as the delegation that officially delivered the nomination to Trump.

“Many people doubted Mr. Trump a year ago and ridiculed those that joined the campaign early on,” Jack said, “but this convention brought the party together and put aside any doubt that we’re organized and ready for November.”

His next assignment is now evolving, but Jack knows he’s moving to the political side of the campaign — with an eye on competitive states. But it will still have a familiar ring to it.

“It’s a new type of counting,” he said. “This time, it’s the Electoral College.”