"I think people today are willing to do things they may not have been willing to do in the past," Secret Service director Joseph Clancy told WTOP.
Clancy pointed out several instances on the campaign trail "where people jumped over those bike racks or security zones into our buffer. In the past, it was very rare for somebody to do that. Today, in this past campaign, people were willing to do it."
Beyond those relatively tame acts, law enforcement officers will be taking precautions including preparing for truck attacks similar to those that took place in Berlin and Nice earlier this year, while staying on watch for more innovative acts of violence.
Paul Abbate, executive assistant director of the FBI’s Criminal, Cyber, Response and Services branch remarked, "We know that this (Washington region) is a high-profile [terror] target. It’s been attacked in the past, historically…We, from the FBI standpoint, are ready to counter terrorist attacks and are working with our partners in building out the intelligence picture."
According to FBI officials, intercepted terrorist communications indicate that Washington DC is named as a potential target for terror attacks on a daily basis.
"We know of no specific credible threat directed toward the inauguration," said Homeland Security secretary Jeh Johnson, who added "that is only part of the story."
Secret Service boss Clancy said that he loses sleep over the possibility of an attack that his team is not prepared for, "Every night I wake up and I wonder do we have some issue covered."
Secret Service officers study worldwide terror attacks and train almost nonstop. They have developed tactics to stop atrocities like the Berlin attack, in which 12 people were killed and 48 injured after a 24-year-old Islamist with ties to Daesh ploughed a truck into the city’s Christmas market.
Officers of the Secret Service have knocked on the door of nearly every home and business near the 1.9 mile-long parade route, asking for details on the occupants’ plans for inauguration day.
Mike Maness, director of private security firm Trapwire believes that domestic terror is the more likely threat. "The bigger threat is probably coming from anti-government/anarchist groups who are likely to try and disrupt the inauguration, and may engage in violence to do so."
Despite his concerns, Maness commented, "From what we have seen the security measures and first-responder preparations have been excellent for the event."
Johnson said, "We've got to be vigilant, we've got to plan, we've got to prepare."