An assault on the President of the United States is a shock to the political and social fabric of the nation. Inevitably, the law enforcement agencies that should have prevented it and those who investigate it fall under scrutiny.
In November 1963, the assassination of President John F. Kennedy devolved into a law enforcement fiasco with conflicts between the FBI, the Secret Service, the Dallas police, and others who would conduct the investigation. It was not yet a federal crime to kill a US president, but in response to that attack, a law was enacted in 1965 making assaulting the president a federal crime, and the new statute was clear: The FBI would lead the investigation.