Nikki Haley and Donald Trump in the Oval Office of the White House, October 9, 2018 (Jonathan Ernst/Reuters)

US Ambassador to the UN Nikki Haley suddenly announces her resignation, surprising the White House and prompting speculation over the reasons.

News of Haley’s resignation, to take effect from the end of the year, broke on the Axios website late Tuesday morning. It quickly spread as the Administration tried to organize a response to damp down thoughts that Haley, a former Governor of South Carolina, is considering a Presidential run in 2020.

Other theories considered in-fighting within the Administration — Haley is at odds with National Security Advisor John Bolton and allied with Trump’s daughter Ivanka and son-in-law Jared Kushner — and a plan for Haley to fill the Senate seat of Trump ally Lindsey Graham as he takes a Cabinet post, possibly that of Attorney General Jeff Sessions.

Finally, a late afternoon appearance of Donald Trump and Haley in the Oval Office was arranged. Haley praised the Administration’s reocrd said:

It was a blessing to go into the U.N. with body armor every day and defend America. I’ll never truly step aside from fighting for our country. But I will tell you that I think it’s time.

Trump responded, “She’s done a fantastic job, and we’ve done a fantastic job together. We’re all happy for you in one way, but we hate to lose you.”

Speculation focused on the prospect that Trump would defy a nepotism statute and name daughter Ivanka to the post. Trump said “would be incredible, but it doesn’t mean I’d pick her”. Ivanka used Twitter to rule herself out:

As he flew to an evening rally in Iowa, Trump said he is considering a short list of five candidates, including former Deputy National Security Advisor Dina Powell.

Powell left the Administration in January to be closer to her family in New York, the site of the UN.

“People close to Haley” insisted that her decision was solely due to fatigue, and that she had given an indication six months ago of the timing of her departure. They said she wanted to announce her decision before mid-term Congressional elections, avoiding embarrassment if Republicans fare badly on November 6.

Some analysts noted that Haley has $1.5 million in estimated debt on her financial disclosure forms, including a $1 million mortgage on her home. That led to assessments that she is hoping to make money in the private sector, perhaps before a Presidential run in 2024.

Citizens for Responsibility and Ethics in Washington, a non-profit watchdog group, claimed on Monday that Haley had violated executive branch regulations on accepting gifts, accepting seven free flights for herself and her husband on luxury private aircraft from three South Carolina businessmen in 2017.