Interesting idea: If some prominent left-wing politician supported extremists and then some of them held target practice, built bombs, and plotted to kidnap or murder a governor, only to be infiltrated and recorded by the FBI, would that politician suffer any consequences? Would they be named as a co-conspirator?

Because that's exactly what happened when Trump supported alt-right extremism and a right-wing militia group plotted to kidnap or kill the governor of Michigan. They are in custody now, but what happens to Trump?