Maricopa County is by far the most populous county in Arizona. In fact, it's one of the most populous counties in the entirety of the United States. Its proximity to the Mexican border has also put it at the forefront of the immigration debate.

For well over two decades, the county's top law enforcement official was Joe Arpaio. Over the years, Arpaio would become one of the most polarizing and infamous public figures in the country. A recent attempt to reclaim his former position has apparently been unsuccessful.

Loses Republican primary for sheriff of Maricopa County

Arpaio was officially declared the loser of the Republican primary for the sheriff's race in Maricopa County. The winner was Jerry Sheridan. Sheridan is a former aide to Arpaio and a 40-year veteran of the department, according to The Hill.

The Guardian indicates that moderate Republicans coming out against Arpaio was a key to the race. He'd lost his post to Democrat Paul Penzone in 2016. Arpaio had become viewed as toxic by many.

By the end of his tenure, allegations of racism against him and the department were plentiful. There were also other allegations, as well, including cruelty, abuse of power, and financial mismanagement.

Arpaio became the subject of federal inquiries about potential civil rights violations.

He was eventually convicted of contempt of court. A month later, he was pardoned by President Donald Trump. Arpaio has maintained his innocence. Which meant he was surprised to hear that by accepting the pardon, it meant he was acknowledging his guilt. Something one might think a long-time law enforcement official would know.

Arpaio is a native of Springfield, Massachusetts. He would serve in the U.S. Army, stationed for a time in France. Later, Arpaio was a police officer in Washington, D.C., and Las Vegas, Nevada. He then became a federal agent with what is now the Drug Enforcement Agency. After multiple international assignments, he became the top official of the agency's Arizona branch.

He'd eventually leave the DEA and become a travel agent. In 1992, he was elected sheriff of Maricopa County and would be re-elected five times.

Arpaio also lost a 2018 U.S. Senate nomination

Arpaio made a run for the U.S. Senate in 2018. Incumbent Republican Jon Kyl was retiring before the end of the term, triggering a special election. Kyl had been a long-time member of Congress. He eventually became a powerful senator, holding Arizona's other U.S. Senate seat. Kyl retired in 2013. But he was appointed to the Senate seat in question earlier in 2018. It was vacated because of the death of iconic Republican Senator John McCain.

In the end, Arpaio finished in a distant third place in the race for the Republican nomination. Instead, the nomination went to U.S. Representative Martha McSally. A former U.S. Air Force colonel, McSally was viewed as the moderate in the race.