Final answer:
There have been several assassination attempts targeting U.S. Presidents, including the failed attempts on James Garfield by Charles J. Guiteau and Franklin D. Roosevelt by Giuseppe Zangara, and the successful assassination of John F. Kennedy by Lee Harvey Oswald.
Step-by-step explanation:
Assassination Attempts on Former Presidents
The question refers to historical incidents involving attempts to harm former Presidents of the United States. One significant event occurred when Charles J. Guiteau shot President James Garfield in 1881 in a failed assassination attempt. Moreover, President-elect Franklin D. Roosevelt narrowly escaped an assassination attempt by Giuseppe Zangara in 1933 while in Miami, resulting in the death of Chicago Mayor Anton Cermak. Another grim moment in U.S. history was the assassination of President John F. Kennedy in Dallas on November 22, 1963, by Lee Harvey Oswald. These notorious attempts on the lives of U.S. presidents underscore the dangers faced by high-profile political figures and the importance of the Secret Service and other protective agencies.