Interesting. By law, Sheriff Arpaio may not have been pardoned, on the grounds that in accepting one a person admits their guilt.
Arpaio denies his guilt and thus may have refused his pardon.
https://www.law.com/njlawjournal/sites/njlawjournal/2017/08/28/accepting-a-pardon-means-admission-of-guilt/?cmp=share_twitter&slreturn=20180318145042