Ahead of what will almost unarguably be the largest concentration of top-tier political power ever assembled in Austin for the Civil Rights Summit at the LBJ Library starting Tuesday, it’s an obvious question: How to secure the event?

It’s also a complex question with elusive answers because of the nature of the work.

The Secret Service, charged with protecting current and former presidents, the latter with considerably smaller details, generally does not discuss the specifics of its security operations.

But we know enough from past presidential visits to expect rolling road closures as the presidential motorcade makes its way from Austin-Bergstrom International Airport — which will go into “airfield freeze” for a short time beginning five to 10 minutes before Air Force One lands until the president departs. The same procedure will be in place when he leaves Austin. That means, according to Jason Zielinski, spokesman for the city’s aviation department, no taking off or landing, no planes taxiing to or from the jetway and no movement of machines or humans on the airfield.

After that, we can expect the president’s motorcade to make its way reasonably rapidly to its campus destination, where agents with faces of stone will be scanning the crowds for potential trouble. We know there likely will be a decoy vehicle identical to the president’s limo in the motorcade, or “package” in Secret Service parlance. Starting Sunday through late Friday, some campus-area streets will be closed and traffic diverted.

What’s less visible, but no less critical, experts say, is the advance work. Add in the fact that three former presidents — Jimmy Carter, George W. Bush and Bill Clinton — will be making appearances over three separate days, and it makes for a unique security situation.

“As soon as an event like this is identified, the Secret Service will want to be the first to know about it prior to it becoming public,” said Don Ellis, a retired FBI agent and attorney who owns Bodyguards of Texas in Tyler. “This initiates a complex flow of security protocols. People see the guys around the president, and they think that’s it. That’s a small part of it.”

With as much time as is available, a lead Secret Service agent will be assigned to coordinate with all law enforcement organizations that will be involved with the visit, Ellis said. Teams of bomb-sniffing dogs from various agencies will have swept the LBJ Library and nearby environs, likely multiple times. A Secret Service advance team will also have conducted a visit to the nearest hospital to plan various scenarios in the event of a medical emergency. In this case that is University Medical Center Brackenridge, the only Level I trauma center in Central Texas.

The Secret Service also has virtually unlimited access to data collected by the American intelligence community, which would factor into its planning for an event such as the summit. On the day or days of the event, Ellis said, it will coordinate with myriad agencies, which in this case would include Austin police, Texas Rangers, Travis County sheriff’s deputies and constables, and others. Those agencies likely will form an outer security perimeter around the event as well as assist in the presidential motorcade when President Barack Obama visits Austin on Thursday.

The middle perimeter, according to Ellis, will consist of a mix of Secret Service and local law enforcement, with “black ops” teams integrated into the inner perimeter.

“The inner perimeter is such a small part of it, but those guys are what people think of,” Ellis said. “They have the cool communications equipment. They have certain weapons designed specifically for the Secret Service. The bullets are designed for them. The various technologies I can’t get into, but rest assured there will be technologies used for that event that 99 percent of the people don’t have a clue even exists. They’ve got some great stuff. And of course they’ll have snipers. They’ll be up there, and the bad guys won’t be up there.”

In a branch of government service reportedly harder to get into than Harvard, the inner circle of longtime agents is the best of the best. They will watch spectators’ hands — and demand to see them if they can’t — and be on the lookout for any sudden movements.

But for all the high-tech accouterments, the life of a Secret Service agent isn’t an exotic one, Ellis said. Travel wreaks havoc on body clocks and marriages. There’s a lot of standing around hotel hallways, bracing for something bad to happen.

“A lot of times they can’t tell their friends or family where they’re going,” Ellis said. “You’re on the battlefield. All your adrenaline is going. You live like that on a daily basis, and it’s like being a soldier on alert.”

More coverage online

Visit www.statesman.com/lbjsummit for the latest updates on the summit, including:

• Join the conversation at our social media hub.

• Daily video live streaming of the conference.

• The Road to Desegregation: An interactive timeline.

• History buff? Take our quiz on civil rights.

• The latest tweets from and about the conference.

• What else to do while you’re in town for the summit.

• Share your civil rights story and read others’.

• Conversations with newsmakers including President Jimmy Carter and San Antonio Mayor Julián Castro, plus commentary from experts and community leaders.

Coming Sunday

A look at LBJ’s civil rights legacy, A1

Q&A with LBJ biographer Robert Caro, Insight

Q&A with LBJ Library Director Mark Updegrove, Viewpoints

Coming Monday

How the summit came to be, A1

Readers share their civil rights stories, Viewpoints

Coming Tuesday

Austin’s road to civil rights, A1

©2014 Austin American-Statesman, Texas