Facing impeachment over an extramarital affair and campaign finance inquiry, Missouri Governor Eric Greitens has announced he will quit on Friday.
The first-term governor was considered a rising Republican star until allegations emerged he had photographed a naked woman without her consent.
The ex-Navy Seal called the allegations a “political witch hunt”.
The Rhodes scholar and father-of-two presented himself as a family man during his 2016 campaign.
The Missouri General Assembly, which is controlled by the governor’s own party, has been considering whether he should be impeached.
What did Greitens say?
“The last few months have been incredibly difficult, for me, for my family, for my team, for my friends and for many, many people that I love,” the 44-year-old said at Tuesday’s news conference.
He added: “This ordeal has been designed to cause an incredible amount of strain on my family.”
Mr Greitens said he had not broken any laws.
He concluded: “For the moment let us walk off the battlefield with our heads held high.
“We have a good and proud story to tell our children.”
Lieutenant Governor Mike Parson, also a Republican, is taking over as the state’s top politician.
What’s the fundraising controversy?
He was charged last month with felony computer data tampering to obtain a donor list for a veterans’ charity he founded in 2007 without permission for his own political gain.
Earlier on Tuesday, a court ruling added to Mr Greitens’ problems.
A judge gave the governor’s political non-profit group, A New Missouri, until Friday to turn over communications between it and Mr Greitens’ office.
Investigators are looking into whether his campaign illegally co-ordinated with A New Missouri to conceal donors by using shell companies to funnel money.
According to the Kansas City Star, Mr Greitens received $6m (£4.5m) in “dark money” for his 2016 campaign.
Also on Tuesday, an ex-Greitens adviser told a state House investigative panel that the governor’s election campaign had considered illegally soliciting donations from foreign nationals, reports the St Louis Post-Dispatch.
What was the sex scandal?
Earlier this year, it emerged that Mr Greitens had had an extramarital affair with his hairdresser.
A man secretly recorded his wife admitting in March 2015 to the liaisons with Mr Greitens.
The hair stylist alleged that Mr Greitens had taken a photo of her when she was partially nude without her permission and threatened to release the image if she ever told anyone about the affair.
Mr Greitens said he had worked through the adultery with his wife, but denied blackmailing the other woman.
The governor was indicted in February with invasion of privacy, but the charge was dropped this month.