Firebrand tapped to lead US dept that investigated him

President-elect Donald Trump has named incendiary Republican US Representative Matt Gaetz to be his nominee for attorney-general, selecting an ally who has faced Justice Department scrutiny to run the agency.

In a statement announcing his pick, which will be subject to confirmation by the Republican-majority Senate, Trump said Gaetz would root out "systemic corruption" at the Justice Department.

The choice of a 42-year-old congressman who has never worked in the Justice Department or as a prosecutor at any level of government was the latest in a wave of Trump nominations of candidates with scant experience.

Gaetz resigned from the House of Representatives on Wednesday "effective immediately", House Speaker Mike Johnson told reporters.

"It caught us by surprise a little bit," Johnson said of the resignation, adding Gaetz stepped down to quickly start the process of naming a replacement in what is expected to be a closely divided House of Representatives.

Gaetz played an instrumental role in ousting former House Speaker Kevin McCarthy in 2023, which kicked off weeks of chaos in the chamber.

His nomination as attorney-general was met with immediate scepticism by some Senate Republicans, who hold the power to confirm or deny his appointment.

"I don't think it's a serious nomination for the attorney-general," Republican senator Lisa Murkowski told reporters.

"This one was not on my bingo card."

Matt Gaetz and Donald Trumo
Donald Trump's ally Matt Gaetz would be in the box seat to radically reshape the Justice Department. (AP PHOTO)

Trump, who faced two federal criminal indictments following the end of his four-year term in 2021, has for years railed against the Justice Department and vowed to radically reshape it when he returns to power on January 20.

Gaetz on Wednesday mused publicly about abolishing the FBI and the Bureau of Alcohol, Tobacco and Firearms and Explosives, or ATF, both Justice Department units.

Trump's inner circle has described the attorney-general, the country's top law enforcement official, as the most important member of the administration after the president, key to his plans to carry out mass deportations, pardon January 6 rioters, and seek retribution against those who prosecuted him during the past four years.

Gaetz himself was investigated by the Justice Department for nearly three years over sex-trafficking allegations involving a 17-year-old girl.

His office said in 2023 that prosecutors had told him he would not face criminal charges.

The Florida congressman, first elected in 2016, remains under investigation by the House ethics committee over allegations of sexual misconduct, illicit drug use and potential attempts to obstruct the probe.

Gaetz denies the claims.

Trump also faced Justice Department investigations after leaving office in 2021, leading to two criminal indictments accusing him of attempting to overturn his defeat in the 2020 election and illegally holding on to sensitive national security documents.

Trump loudly objected to both cases, accusing the Justice Department under Democratic President Joe Biden of being turned against him to damage his political prospects.

A federal judge appointed by Trump threw out the documents case, and the election case is expected to be dismissed due to Trump's election victory.

Former Justice Department officials said they worried Gaetz would seek to politicise the operations of the traditionally independent agency.

Gaetz worked at a Florida law firm before being elected in 2016, the year Trump was first elected.

Hours before Trump announced his nomination, Gaetz posted on social media: "We ought to have a full court press against this WEAPONIZED government that has been turned against our people. And if that means ABOLISHING every one of the three letter agencies, from the FBI to the ATF, I'm ready to get going!"