I thought this when I heard about the Manson chick was charged with attempting to shoot president Ford, when apparently it was an unloaded gun.
Interestingly, two women have been done for attempting to murder a president; both of which was against Ford within the same month within a small radius (maybe 100 miles).
I think generally anything that is considered an attempted <whatever>, the judicial system takes into account the intent of the person who is being accused. If the intent was to assassinate Trump, and the person had everything they needed to do it, and would have done it if they had not been stopped, then a real attempt was made.