Duke did not advocate violence, but Southern Poverty Law Center spokesman Mark Potok says Duke's message is part of the recent wave of "worrisome vitriol" directed at the president-elect.
"There is a real fury out there; a boiling rage," Potok says.
Mey says security for this inaugural likely will be tighter than for any other — including President Bush's 2005 inauguration, the first after the 9/11 terror attacks. For that event, fighter jets patrolled the skies over the capital, radiological sensors were located in the city's Metrorail system and Coast Guard units monitored the local rivers.
"I would expect (this) inauguration to be completely buckled down," he says.
City under surveillance
Despite Washington's long experience dealing with large gatherings — from Fourth of July celebrations and global summits to demonstrations on the National Mall — Burke describes inaugurations as the "biggest challenges." Protection for visiting dignitaries, street closures and sprawling outdoor venues require a meticulously choreographed security operation.
Since 9/11, Washington has installed a network of dozens of surveillance cameras that allow officials to more easily monitor multiple locations during major events.
Mey says the camera technology is key to the security effort, adding a layer of protection to the thousands of officers in uniform and those roaming the crowd in plainclothes.
"You never really have it down to a science," Burke says of security planning.
Jesse Jackson, a two-time Democratic presidential candidate who says his campaigns drew scores of threats, says the nation's "legacy of violence" requires a large security presence.
Obama "must be careful," Jackson says. "He just can't be wandering into any crowds."
Jarvis, the former Secret Service agent, says the risks brought to life by the 9/11 attacks and other tragedies, including the assassination of President Kennedy in 1963, are simply too great to dismiss.
"The consequences?" Jarvis asks. "Nobody wants to think about it."