...just have a prosecutor sign it, and then take a prosecutor's law license and put FBI agents in jail if they abuse their powers.
Probably not workable. But his point was that judges trust the authorities...and in political cases like this, they are loathe to punish abuses by their own political party (which further policies the justice system). And the FBI (and Conor) use the judge's signature as cover, knowing it is disingenuous, and they will get away with it.
Sadly, the Right needs to start abusing power like the Left does before the Left will agree to stop. Otherwise, they will just keep doing it, and claiming they want a nation of laws enforced fairly each time (while not wanting enforcement on their own).