Matt Gaetz, a Bomb-Thrower for the Justice Department

In selecting Representative Matt Gaetz to be his attorney general, President-elect Donald J. Trump has chosen an undisguised attack dog to preside over the Department of Justice.

Mr. Gaetz, 42, a Florida Republican and an unswerving loyalist to Mr. Trump, has a history that under conventional circumstances would make his confirmation prospects appear insurmountable.

He was investigated by the Justice Department on suspicion of child sex trafficking. This year, after the government case was shuttered, the House Committee on Ethics opened its own inquiry into the matter, which effectively ended on Wednesday night after Mr. Gaetz resigned from his seat. Mr. Gaetz has also been accused of showing photos of nude women to colleagues on the House floor and of seeking a pardon from the previous Trump White House. He has denied each of these allegations.

Mr. Gaetz is also an avowed enemy of virtually every top Republican not named Trump. He led the charge last year to oust one Republican leader, Speaker Kevin McCarthy, and this year openly celebrated the resignations of two others — Senator Mitch McConnell, who announced he would be retiring as minority leader, and Ronna McDaniel, who stepped down as chairwoman of the Republican Party National Committee.

“We’ve now 86’d: McCarthy, McDaniel, McConnell,” Mr. Gaetz exulted on the social media platform X in March.

“I am not some ‘Lord of the Flies’ nihilist,” Mr. Gaetz insisted to The New York Times in January 2023, just after he had relinquished his five-day blockade of Mr. McCarthy’s eventually successful quest to be speaker. But nine months later, Mr. Gaetz helped pushed Mr. McCarthy out of the job for good.