I think Trump is afraid of pissing off the establishment. The FBI has been criminally investigating Trump literally his entire time as president. The Mueller in

I think Trump is afraid of pissing off the establishment. The FBI has been criminally investigating Trump literally his entire time as president. The Mueller investigation is over but the SDNY office is still investigating his finances hoping to find something they can nail him on. It's also been reported that Mitch McConnell threatened to support the impeachment if he pardons Assange. Though this claim has not been substantiated.