Joe Arpaio, the tough-guy former sheriff of Maricopa County, Arizona, announced Sunday that he's running for his old job, exactly two years after President Donald Trump pardoned him for a federal contempt of court conviction.

"Watch out world! We are back!" Arpaio, 87, said in a statement in which he promised to reinstate the extreme measures that made him famous, like housing immigrants in outdoor tents in the 100-degrees-plus temperatures of the Phoenix area.

Arpaio was defeated for re-election to what would have been a record seventh term as sheriff in November 2016, shortly after he was charged with contempt of court for having ignored a federal judge's order to stop arresting immigrants solely on suspicion that they were in the country illegally.

Arpaio, who was one of the first elected officials to endorse Trump's presidential campaign, was convicted in July 2017. The next month, Trump pardoned him, saying he admired Arpaio's work "protecting the public from the scourges of crime and illegal immigration."

Last year, Arpaio lost a Republican primary race for the U.S. Senate to Rep. Martha McSally.

Arpaio reveled in his reputation as America's toughest sheriff, which led him to be the target of several civil rights lawsuits. He boasted that:

He forced inmates to wear pink underwear.

He fed inmates only twice a day with a bland log called "Nutraloaf," which other prisons serve as a disciplinary measure.

He subjected inmates to an in-house radio station that played patriotic music and opera for 20 hours a week. He called the station KJOE.

In 2008 and 2010, a federal judge ruled that Arpaio's jails violated the constitutional rights of inmates when it came to medical care.

Arpaio was also famous for housing prisoners in outdoor tents that he himself called concentration camps, where inmates complained that fans were inoperative and that their shoes melted.

He was reported to have responded to the complaints by saying, "It's 120 degrees in Iraq, and the soldiers are living in tents, and they didn't commit any crimes, so shut your mouths."

Alessandra Soler, executive director of the American Civil Liberties Union of Arizona, on Sunday called Arpaio a "racist" who should "never hold public office again."

"When Joe Arpaio talks about 'those who break the law,' he should be referring to himself," Soler said, adding: "President Trump might've pardoned him, but those who had families and communities destroyed by his unlawful tactics have not."

In his announcement Sunday, Arpaio lamented that "the last four years have proven to be a time of lost opportunities to continue the kind of tough policing this county needs."

Joe Arpaio announces 2020 bid for 7th term as Sheriff.



Thousands want me to run for Sheriff. Today Aug 25 announcing run for Sheriff Important day for me. Wife's Birthday & Pres Trump Pardoned me. Ready for bruising, bitter campaign. Never back down.https://t.co/4dkuVCtCUa — Sheriff Joe Arpaio (@RealSheriffJoe) August 25, 2019

And he warned that his enemies would do their worst to make sure he isn't re-elected.

"During the past several years, his opponents, activists and political figures on the Left, have utilized slanderous attacks on him through the fake and biased news media to try and keep him from being heard, but these efforts have failed," the statement said. "However, he expects these attacks will continue in full force, even more so with today's announcement."

His opponents are likely to include Jerry Sheridan, who strongly supported him as his chief deputy for the last six years Arpaio was sheriff.

Sheridan announced in February that he is also seeking the Republican nomination to challenge Sheriff Paul Penzone, who defeated Arpaio with 56 percent of the vote in 2016. He said Sunday that he would remain in the race.

"My focus has always been on getting the bad guys, not headlines," Sheridan said in a statement, according to NBC affiliate KPNX of Phoenix. "We need a professional and proven lawman to win this office back and the voters have already made it clear they will not vote for Joe."

CORRECTION (Aug. 25, 2019, 9:05 p.m. ET): A previous version of this article misstated how Rep. Martha McSally, R-Ariz., moved to the Senate. McSally lost the 2018 Senate race to Rep. Kyrsten Sinema, a Democrat, and was appointed to the Senate in December 2018 after Jon Kyl resigned.