Joe Arpaio

Maricopa County Sheriff Joe Arpaio is surrounded by protesters and members of the media at the site of the Republican National Convention on July 19th, 2016, in Cleveland, Ohio.

Arpaio, who was pardoned by Trump last year for a contempt of court charge, has promised to give his full support to the president.

By Kate Wheeling

NewUpdate

The federal agency is arguing that a presidential pardon "moots a criminal case."

By Kate Wheeling

Maricopa County Sheriff Joe Arpaio is surrounded by protesters and members of the media at the site of the Republican National Convention on July 19th, 2016, in Cleveland, Ohio.

The presidential pardon power is limited only by shame and politics, one expert says, and Trump is beholden to neither.

By Kate Wheeling