Spewing a bunch of junk on Twitter or trying to drop cases against people swept up by the Trump Russia investigation or pardoning them is one thing but if they're actually going to actually file criminal charges against anybody within the FBI, they're going to have to have damning evidence that 9 impartial jurors and/or a Judge will have to find good enough to convict and failing to do so would backfire tremendously. Even considering what bad shape things are in right now in terms of the judiciary, DOJ still can't just waltz into any old courtroom and conduct show trials. Also, didn't they already decide NOT to indict or try to charge Andrew McCabe (most likely because they couldn't find anything to charge him with)? Their main weapon right now seems to be just trying to splash doubt and discredit what has already been done and the investigators, which doesn't require that they prove anything in a court of law, although I can't imagine that they aren't making a lot of enemies in the FBI and intel agencies with their conduct. I now see that they are going after Christopher Wray at the FBI, who must not be toadying up for Trump as much as he would like if he is now eyeballing him as somebody he might want to get rid of. Outright firing TWO FBI Directors in one term is probably going to prove to be too much for most, however, so Trump and/or Barr are probably working some low-key angles to figure out how to get rid of him.