Nixon and others received a pardon before they were even charged with a crime or indicted.
He's trying to have his conviction overturned -- and he apparently has legitimate reasons for this.
The people whose involvement in this case has now been reduced to a joke are the U.S. Justice Dept. lawyers who prosecuted the case. They have to go through a silly court proceeding to fight Arpaio's attempt to have his conviction overturned ... while knowing that Arpaio has been granted a pardon by their own boss anyway. They have to be thinking that this is a total waste of their time. Maybe they're considering a career doing something more respectable like running a meth lab or dealing heroin.