I understand why he has to do this. The entire GOP is as wedded to the idea of the "weaponization of the DOJ" as they are to Trump. But I'm not sure what kind of lane that is for winning. His only hope at winning is that Republicans move away from Trump as the legal issues mount, but here he is attacking that very legal system. Republicans aren't going to take the legal issues seriously if they think this has all been weaponized against Trump.
It’s probably an oversimplification, but I tend to think they’ve all been so complicit in his misconduct over the previous few years that an indictment or - better - a conviction might not bode well for them too. So attack the system they must.