But his latest entanglement in the courts is his toughest test yet after he acknowledged to a judge presiding over his racial-profiling case that his office was behind a secret investigation into the judge's wife.

The disclosure came as Arpaio testified in a contempt of court hearing convened after he admitted disobeying the judge's order to stop his signature immigration patrols as part of the profiling lawsuit.

The revelation has raised questions about whether Arpaio can win a seventh term next year.

David Berman, a senior research fellow at Arizona State University's Morrison Institute for Public Policy, said the upcoming election represents the most likely possibility yet that the sheriff could get voted out of office.