He Was Ordered [by the judge] Not to Enforce Federal Law
According to the more excitable opponents, pardoning Arpaio would be an endorsement by Trump of racism. This plays into the narrative of the left that Trump himself is a racist. One racist pardoning another is the way it is being framed.
But Arpaio wasn’t criminally convicted for illegally using race in traffic stops. He was criminally convicted for turning illegal immigrants over to federal officials. And here things get messy.
Federal law explicitly authorizes local law enforcement to communicate with federal officials about the immigration status of those they encounter. State law requires local law enforcement to follow up on reasonable suspicion of illegal presence when practical to do so.
So, arguably, Snow’s order prohibited Arpaio from doing what federal law allows and state law mandates. When Trump said in Phoenix that Arpaio was convicted for doing his job, there’s a basis for that point of view.