Two things here" First, I think Trump took the sensitive information in order to deprive Biden and his administration of such information in the event of a national crisis, thereby hobbling a Biden response and forcing Biden to go to him for info (a cheap Trump power play, which is his only kind). That in itself is treasonous. Second, the FBI knows stuff, including stuff about many of the Republicans, so if the GOP wants a full on bare-knuckles fight with the FBI, they may regret it, as the FBI will land some nasty blows of their own.