US Attorney-General Jeff Sessions has been pushed after enduring more than a year of blistering and personal attacks from President Donald Trump, who inserted in his place a Republican Party loyalist with authority to oversee the remainder of the special counsel's Russia investigation.
The move has potentially ominous implications for special counsel Robert Mueller's probe given that the new acting attorney-general, Matthew Whitaker, until now Sessions' chief of staff, has questioned the inquiry's scope and spoke publicly before joining the Justice Department about ways an attorney-general could theoretically stymie the investigation.
Congressional Democrats, concerned about protecting Mueller, called on Whitaker to recuse himself from overseeing the investigation in its final but potentially explosive stages.
That duty has belonged to Deputy Attorney-General Rod Rosenstein, who appointed Mueller and closely monitors his work.
The resignation, in a one-page letter to Trump, came one day after Republicans lost control of the House of Representatives and was the first of several expected post-midterms Cabinet and White House departures.
Though Sessions was an early and prominent campaign backer of Trump, his departure letter lacked effusive praise for the president and made clear the resignation came "at your request."
"Since the day I was honoured to be sworn in as attorney-general of the United States, I came to work at the Department of Justice every day determined to do my duty and serve my country," Sessions wrote.
The departure was the culmination of a toxic relationship that frayed just weeks into Sessions' tenure, when he stepped aside from the Russia investigation because of his campaign advocacy and following the revelation that he had met twice in 2016 with the Russian ambassador to the US.
Trump blamed the recusal for the appointment of Mueller, who took over the Russia investigation two months later and began examining whether Trump's hectoring of Sessions was part of a broader effort to obstruct the probe.
Trump had repeatedly been talked out of firing Sessions until after the midterms, but he told confidants in recent weeks that he wanted Sessions out as soon as possible after the elections.
Rosenstein remains at the department and could still be involved in oversight.
In a CNN op-ed last year, Whitaker wrote, "Mueller has come up to a red line in the Russia 2016 election-meddling investigation that he is dangerously close to crossing."
Trump's relentless attacks on Sessions came even though the Alabama Republican was the first US senator to endorse Trump and despite the fact his crime-fighting agenda and priorities, particularly his hawkish immigration enforcement policies, largely mirrored the president's.
But the relationship was irreparably damaged in March 2017 when Sessions, acknowledging previously undisclosed meetings with the Russian ambassador and citing his work as a campaign aide, recused himself from the Russia investigation.
The broadsides escalated in recent months, with Trump telling an interviewer that Sessions "never had control" of the Justice Department.
Sessions endured most of the name-calling in silence, though he did issue two public statements defending the department, including one in which he said he would serve "with integrity and honour" for as long as he was in the job.
Australian Associated Press