Fascist paramilitary thug threatens to arrest US citizen for exercising his 1st amendment rights
(cdn.social.linux.pizza)
The determination is made whether or not the threat can be proven to be true.
If I say I'm going to kill the president and it's proven that 1) I've taken no actual steps toward a plan and 2) I don't have the means to do so anyway - the threat is considered 'untrue'.