Based on 58 multi-hour interviews and more than 7,000 documents, the independent bipartisan panel President Joe Biden assigned to analyze the Secret Service after the attempted assassination of Donald Trump this summer issued a grim warning: Without fundamental reforms to the agency, what happened in Butler, Pennsylvania, on July 13 “can and will happen again.” These changes, even more than the specific events of the rally, ought to be the focus going forward.

To be sure, the facts are stunning, as they appear not only in the independent panel’s report but also in an interim report from a bipartisan House of Representatives task force and a separate Senate committee investigation. Basically, these documents describe a day of disarray. The Secret Service neglected to secure the building from which the gunman fired the shot that grazed the former president’s ear, it left open possible lines of sight from there to the podium where Mr. Trump stood, and it set up so chaotic a communications structure that no one informed the leaders of Mr. Trump’s detail about the man they’d seen lurking on-site, even after he made it onto the roof.

The would-be assassin was able to operate a drone for 11 or so minutes undetected only hours before he took aim at his target. Soon after that, he was identified as suspicious by a local countersniper going off duty — and again, and again, by other state and local law enforcement personnel as he popped in and out of view, at one point examining the rally stage area with a range finder.

The panel suggested concrete remedies for these very specific failings: Ensure agents in charge of advance and day-of work for sensitive events have sufficient experience. Have the lead site agent furnish the head of the protectee’s detail with an in-person report upon arrival at a given event. Coordinate more closely with state and local partners. Create a central command center at every event that can respond to incidents in real time.

All of this was so clear that the Secret Service made similar points in its own report. More controversial, and subject to pushback from the agency, are broader critiques of its culture and structure. The independent panelists pointed to an ingrained lack of initiative and outside-the-box thinking: Shouldn’t agents have spoken up more forcefully when they saw a suspicious person and pursued the issue until they were sure they’d been heard? Shouldn’t, as a rule, the Secret Service do everything it can to marshal resources needed for a mission’s success, rather than try to “do more with less”?

The new acting director of the Secret Service, Ronald L. Rowe Jr., acknowledged in September that the summer’s failure resulted in part from “complacency” on the part of some agents — and emphasized that the service has adopted a posture of “hyper-vigilance.” Many improvements, he said, will require additional personnel and equipment. That’s a reasonable ask: A bigger budget could enable better training, including simulations of lifelike scenarios. And, admittedly, the agency is not entirely to blame for the strain it has fallen under. The Secret Service can’t cool the country’s overheated political climate.

The more difficult question is how to effect broader systemic change at the agency. The independent panel, for its part, suggests that the agency refocus on its “core protective mission.” This protective mission, in fact, has only been primary during the modern era; the Secret Service at its 1865 founding was housed in the Treasury Department and responsible primarily for detecting counterfeiting and a few other federal crimes. Over time, the agency, now part of the Department of Homeland Security, evolved to fill the role it performs today of keeping the nation’s leaders, former leaders and their families safe. Yet it still has an investigations division tasked with ferreting out counterfeiters, computer fraud and more.

Many if not most Americans would probably be surprised to learn the Secret Service is still involved in such matters, given that there are so many other federal bodies with similar competencies — notably, the Federal Bureau of Investigation. There is an argument that the skills Secret Service personnel hone during investigative duties can help with protection. But there’s also an argument that those other missions distract from the essential job of preventing political destabilization via assassination.

The independent panel recommended subordinating the investigations division tothe protective division, but this seems like a limited shift in the organizational chart. Congress ought to consider more radical changes, including assigning the Secret Service’s 19th-century mission to someone else in the 21st.