This is one more news story that is bringing me to the conclusion that the FBI didn't cause this person to commit an act that but for the FBI he would not have committed. [FBI: Portland bomb plot suspect wrote for jihadist magazine].
The 'igniting' of an inoperable bomb by this suspect is sufficient in itself to warrant a guilty verdict. It is not like the FBI used their wiles to convince someone to sell drugs to an undercover agent. Irrespective of how this person came to the point of pushing the button, and push it he did, he knew the likely results. This should eliminate any "predisposition" defense.
Look had he in fact ignited an actual bomb in downtown Portland - would we be considering some predisposition defense? See this all too similar story without the FBI role except to stop the bombing: New York Fed bombing plot proves the terror threat is real. Although the details of the FBI and New York cops are scant - it seems clear that predisposition is not a defense.
Sometimes the act itself is sufficient to convict.