There is evidence that Sheriff Arpaio was denied a fair trial

Power Line:

...
7. During several days of hearing, Judge Snow

-asked leading questions,
-gave his own version of the facts,
-conducted his own investigation outside the courtroom,
-argued with witnesses, and
-was extremely interested in what evidence existed concerning the statement he made to his wife that he would do all that he could to make sure that Sheriff Arpaio is not elected.

8. One thing is very clear. Several witnesses heard Judge Snow’s wife say, in substance, that her husband (Judge Snow) wanted to do whatever he could to make sure that Sheriff Arpaio [was] not reelected. The witnesses may not recall or agree on the exact language that Judge Snow’s wife used, but they do agree on the substance and import of the statement.

9. Judge Snow has never denied making such a statement under oath. In fact, he has never denied it at all.
...
13. [I]n the case of Melendres v. Arpaio [the case that is the vehicle for Snow’s investigation of Arpaio], the brother-in-law of Judge Snow is a partner in Covington & Burling, the law firm representing the plaintiffs. It is, as I understand it, a lucrative case for Covington.

The Federal Ethics Advisory Committee says under Canon 3(C)(1)(d)(ii), the judge must disqualify if the brother-in-law is “acting as a lawyer in the proceeding,” or if, under Canon 3(C)(1)(d)(iii), the brother-in-law is “known by the judge to have an interest that could be substantially affected by the outcome of the proceeding.” The Committee [states] “that an equity partner in a law firm generally has ‘an interest that could be substantially affected by the outcome of the proceeding’ in all cases where the law firm represents a party before the court.”
...

There is much more.

I felt that Arpaio was the victim of a political persecution all along and this additional evidence suggest ethical problems by the court that heard the case.   This adds more merit to the Trump pardon of Sheriff Arpaio.