Threat Analysis

Wikipedia:

Ford faced two assassination attempts during his presidency, occurring within three weeks of each other: while in Sacramento, California on September 5, 1975, Lynette “Squeaky” Fromme, a follower of Charles Manson, pointed a Colt 45-caliber handgun at Ford. As Fromme pulled the trigger, Larry Buendorf[70], a Secret Service agent, grabbed the gun and managed to insert the webbing of his thumb under the hammer, preventing the gun from firing. It was later found that, although the gun was loaded with four bullets, it was a semi-automatic pistol and the slide had not been pulled to place a bullet in the firing chamber, making it impossible for the gun to fire. Fromme was taken into custody; she was later convicted of attempted assassination of the President and was sentenced to life in prison.[71]