Former attorney-general Christian Porter has announced he will be stepping away from politics, citing his experience dealing with the "harshness of modern politics".
Mr Porter said on Wednesday evening he will not recontest his Western Australian seat of Pearce at the next federal election, which is expected to be held in March or May.
The announcement comes amid speculation Health Minister Greg Hunt will announce his retirement on Thursday - federal parliament's final sitting day of the year.
Mr Porter's decision to quit federal politics completes a spectacular downfall for a man once touted as a future Liberal prime minister.
"I have spent the best part of the last 20 years in public service," Mr Porter said via a post on his Facebook page.
"This week however, I made the decision that I will not recontest the seat of Pearce at the next federal election and I have informed the Prime Minister of that decision.
"Before each election I have always asked myself whether I could absolutely guarantee another three years of total commitment to the electorate because people deserve that commitment, free of any reservations.
"After a long time giving everything I could to the people of Pearce it's now time to give more of what is left to those around me whose love has been unconditional."
Mr Porter's looming departure had been rumoured for weeks.
Ms Milligan was the author of an online article in February which revealed an unnamed cabinet minister was the subject a historic rape allegation.
Days later, a tearful Mr Porter outed himself as the accused minister. The then attorney-general rejected the allegations.
His decision to launch defamation action against the ABC prompted him to resign as the nation's first law officer.
Parliament's privileges committee this week cleared Mr Porter over his blind trust, but recommended the rules be updated.
In his statement on Wednesday, Mr Porter took another swipe at his critics.
"There are few, if any, constants left in modern politics. Perhaps the only certainty now is that there appears to be no limit to what some will say or allege or do to gain an advantage over a perceived enemy," he said.
"This makes the harshness that can accompany the privilege of representing people, harder than ever before. But even though I have experienced perhaps more of the harshness of modern politics than most, there are no regrets."
A former crown prosecutor in his home state, Mr Porter served as Western Australia's attorney-general and treasurer before switching to federal politics in 2013.
He held a number of portfolios during his eight years in Canberra, including social services, industry, science and technology, industrial relations and attorney general.
More to come.