"It should not have happened. And it won't happen again," Secret Service Director Joseph Clancy said in an interview with CNN.
A 27-year veteran Secret Service agent who understands life inside the president's sensitive protective detail, Clancy came out of retirement last year to lead the troubled agency after his predecessor was effectively fired following a string of embarrassing headlines.
Beyond the dismissal of the agency's director, the fence-jumping incident triggered sweeping changes inside the Secret Service's insular upper-echelon of managers. Because of that and other sordid episodes, Clancy is battling the conventional wisdom in Washington that only an outsider can restore the public's trust in the Secret Service.
"I do think it helps to have some kind of baseline education of this job. It's a difficult job," Clancy said. "I don't think it's a cultural problem. I think that we've certainly had an element that's had some difficulties in the past. We've honestly moved on from that. We've learned from our mistakes."
The Secret Service is attempting to change course as it rebuilds from the ground up. Clancy is investing heavily in the agency's recruitment and training program that conducts intensive drills at a facility in the Maryland suburbs of Washington.
Forced budget cuts from government sequestration in the last several years had dramatically reduced training class sizes to only a handful of recruits. But that trend has since been reversed, as the agency is now preparing nine separate classes of more than 20 trainees this year alone, Secret Service officials said.
Reporters were invited by the agency to observe some of its training on a recent steamy July morning. The exercises included a demonstration of the Secret Service's K-9 squads -- namely the officers who work with the world-reknown Belgian Malinois dogs used to subdue White House fence jumpers.
"I want to talk to the president," one agent screamed, posing as a suspect during one drill. Standing in a large padded "bite suit," as it is called, the Secret Service officer is subdued within seconds by one of the agency's dogs.
There were other classic exercises on display, from evasive driving drills that test an agent's ability to flee a roadway attack on the presidential motorcade to simulated ambushes. Journalists stood back as flash grenades exploded and gunfire ensued.
Clancy said he also has his eye on more modern threats, whether it is a drone flying over the White House fence or an attack on a presidential candidate from an ISIS inspired terrorist, a part of the new reality for 2016 contenders and their campaigns.
"Absolutely. We are heading towards that," Clancy said about training with ISIS threats in mind. "But we're also training toward the lone wolf. There's a multitude of threats out there as there have been throughout our history," he added, noting the Secret Service is celebrating its 150th anniversary this year.
Preparing for the unmanned aerial threat to the White House is a subject Clancy declines to discuss at any length.
"I'm not going to get into specifics here," Clancy insisted. "But we have included some new technology there at the White House," he added.
Despite the pleas from frustrated lawmakers for more transparency and speedier reforms, officials inside the agency caution they cannot make changes overnight.
Just last week, the Secret Service added spikes atop the White House fence to thwart jumpers, a temporary measure that came more than nine months after September's infamous intrusion.
Clancy acknowledged the new deterrent would only go so far, until a taller fence around the White House can be constructed. The Secret Service must await congressional approval to fund the larger fence project.
"We're hopeful that it will give us time, a little bit of time," Clancy said of the spikes. "It won't stop every jumper," he added, conceding the White House fence could easily be scaled if left unprotected.
Clancy recalls he was working in the private sector, as head of corporate security for Comcast Television, when the White House intruder attempted the unthinkable last fall. The director said his immediate reaction was one of deep concern about what the agents involved must have felt.
"I know they were pained by that. They've dedicated their lives to protecting the president and vice president and the White House," he said.
Clancy pointed to the ambush drill as a reminder of what is at stake for each Secret Service trainee. The exercise takes place in a mock village at the intersection of two roads, 15th street and Clint Hill Way.
Hill, as all Secret Service personnel must know, is the legendary agent who was on the detail assigned to protect President John F. Kennedy in Dallas on November 22, 1963. The agent's agony of losing a commander-in-chief to an assassin's bullet was immortalized in the Clint Eastwood film based on Hill's life, "In the Line of Fire."
Clancy said he still speaks to Hill and other former special agents in charge of the Secret Service every year.
"I always think about Clint Hill and all of our people should because you never what's going to happen at any time," Clancy said.