During the event, 20-year-old Thomas Matthew Crooks was able to fire at Trump from atop a nearby roof. A Secret Service sniper returned fire, killing Crooks.
The Secret Service has faced intense criticism for security at the Butler rally, with an internal assessment concluding that the agency was responsible for stunning lapses in planning and communications.
The attack ignited bipartisan outrage, spurred multiple reviews examining security failures and fuelled calls for the Secret Service to undergo significant reforms.
Soon after the shooting, Secret Service Director Kimberly Cheatle resigned amid pressure. Her successor, Ronald Rowe, served about six months as acting director, and he has acknowledged that the Butler attack “was a failure of the Secret Service” to secure the area or protect Trump.
This year, Trump, who months after the shooting was elected president for a second time, tapped Sean Curran - a longtime agent who had headed Trump’s Secret Service detail and helped shield him on the Butler stage - to serve as the agency’s director.
“Nothing is more important to the Secret Service than the safety and security of our protectees,” Curran said in a statement released by the agency.
“As director, I am committed to ensuring our agency is fully equipped, resourced, and aligned to carry out our important mission each and every day.”
The Secret Service said today that it had enacted numerous reforms since the Butler shooting, including measures aimed at improving accountability, boosting communication with state and local authorities and beefing up intelligence sharing before and during events requiring protection.
Assessments of the Secret Service’s actions in Butler have been withering, with reviews sharply criticising the way the agency and its agents behaved before, during, and after the shooting.
An internal review found that the Secret Service never directed local police snipers to monitor a nearby rooftop, despite the snipers’ willingness to do so.
That review also found that the Secret Service had its own security room that was separate from a command post for Butler County Emergency Services and also used a different radio frequency from local law enforcement officials, hindering them from rapidly sharing information.
Another review conducted by an independent panel said the Secret Service needed “fundamental reform to carry out its mission”, which includes providing security for presidents, former leaders and other top US officials.
This bipartisan panel highlighted multiple security breakdowns and found that some agents involved in Butler security were inexperienced.
The panel’s review also found that agents “appear to have done little in the way of self-reflection in terms of identifying areas of missteps, omissions, or opportunities for improvement”.