I don't know about the US law, but in at least some european countries (like austria, where I grew up) "getting guidance with the purpose to commit terrorist attacks" is actually crime. As well as "approval of terrorist attacks" (which are quite liberal defined).
In my expectation, the US should not be too far "behind" on prosecuting those thought crimes.
"Thought crime" like conspiring to commit murder is also a crime, as it turns out.
But then it's not really a strict thoughtcrime in the 1984 sense either, since it does still involve overt acts. E.g. simply saying that 'terrorists are cool' wouldn't get you charged, but starting a specific plot to conduct an attack and taking actions to advance that plot could, even if those "actions" are simple matters of coordination and communications... again, just like for ordinary homicide.
"E.g. simply saying that 'terrorists are cool' wouldn't get you charge" ...in austria? Yes, if you do it in front of 30 or more people (definition of "in public") it would get you charged. Well, of course not in the form of an obvious joke like "terrorists are cool" but if the prosecutor sees it as an "approval" of terrorist attacks.
