It's a fact. No president has been successfully assassinated since JFK.
Indeed, the first president to acquit the turkey was John F. Kennedy, who decided to spare the bird donated to his White House in 1963.
Just four days before an assassin’s bullet ended his life, Kennedy returned his donated gobbler back to the farm saying, “We’ll let this one grow.” While no one in the White House referred to the act as a “pardon,” some newspapers used the term in jocular stories of the bird’s fate.
The first president to formally use the term “pardon” to characterize his sparing of the Thanksgiving turkey was Ronald Reagan who returned Charlie the turkey to the farm in 1987.
Perhaps unsurprisingly, Reagan issued his “pardon” to Charlie as a needle to the media. At the time his administration was under pressure from the press over the Iran-Contra Affair with journalists badgering him as to whether or not he would pardon Oliver North, a man from whom Congress was keen to hear testimony. Still, Reagan did not pardon any turkey other than Charlie during his presidency.
Finally, Reagan’s successor, George H.W. Bush, made pardoning the turkey an official part of the White House schedule during Thanksgiving week, and it has stayed a tradition ever since.