WASHINGTON (AP) - U.N. Ambassador Nikki Haley is resigning later this year in the latest shake-up to President Donald Trump's turbulent administration, the announcement Tuesday raising questions in the White House about the timing and Haley's own possible political future.
  
The news blindsided many congressional Republicans involved in foreign policy matters and some key U.S. allies. It means the departure of one of the administration's highest-profile women and a top official who has offered strikingly different perspectives on world events from her more isolationist-minded boss.
  
Haley, who is not personally wealthy, hinted in her resignation letter to Trump that she is headed to the private sector.
  
"I have given everything I've got these last eight years," she said, referring to her six years as South Carolina governor as well as her time at the U.N. "And I do think it's good to rotate in other people who can put that same energy and power into it."
  
There has been speculation that Haley, the former governor of South Carolina, will return to government or politics at some point.
  
"No, I'm not running in 2020" for president, she joked, quickly adding that she would be supporting Trump.
  
Haley has two children to put through college and the potential to make much more money in the business world.
  
The decision to announce the latest shake-up came less than a month before the congressional elections, even as the White House has made a concerted effort to hold off on major changes - at the Justice Department and elsewhere - before then.
  
Trump was asked why the announcement was made now since Haley is staying until the end of the year.
  
Instead of answering directly, he recounted how she has had to work on tough issues, such as Iran and North Korea.
  
White House officials had sought to put a hold on record-setting administration turnover in the run-up to the Nov. 6 elections, with aides being asked months ago to step down or commit to stay through Election Day to avoid adding to a sense of turmoil.
  
Still, the prospect of post-midterm changes has loomed over the West Wing, and Haley's exit was one of those discussed, according to a senior administration official not authorized to publicly discuss private conversations.
  
Despite Trump's calm words, her sudden announcement rattled a number in the White House, who openly speculated that the timing was meant to preserve the ambassador's own political future, according to the official and another White House official.
  
Trump said Haley first discussed leaving the administration with him six months ago. The official noted that their conversation coincided with the appointment of Mike Pompeo as secretary of state and John Bolton as national security adviser. Haley had expressed some frustration that her voice had been diminished as the two men became the aggressive new faces of Trump's foreign policy, the official said.
  
More recently, there was an awkward moment at the U.N., when Trump's boasting of American economic strength under his leadership drew laughter at a General Assembly session. He insisted later that the delegates were laughing with him, not at him.
  
The six-month timeline also coincides with a high-profile spat between Haley and the White House in April, when she drew the president's ire for previewing in a television appearance the administration's planned imposition of a new round of sanctions on Russia. When the sanctions never materialized, White House officials said the plans had changed without Haley being briefed, and top economic adviser Larry Kudlow suggested Haley was confused.
  
"I don't get confused," Haley said in a sharply-worded rejoinder to the West Wing.
  
Haley, 46, was appointed to the U.N. post in November 2016 and last month coordinated Trump's second trip to the United Nations, including his first time chairing the Security Council.
  
A rookie to international politics, the former South Carolina governor was an unusual pick for to be U.N. envoy. "It was a blessing to go into the U.N. every day with body armor," Haley said, saying her job was to defend America on the world stage.
  
At the U.N., she helped spearhead the administration's efforts to combat what it alleged to be anti-American and anti-Israel actions by the international body, including the U.S. decision to leave the Human Rights Council and to stop funding the U.N. agency for Palestinian Refugees, known as UNRWA.
  
Haley also secured three successively tougher Security Council sanction resolutions against North Korea - which the administration has credited with bringing Kim Jong Un to the negotiating table - and an arms embargo against South Sudan. But under Haley's tenure at the U.N., the U.S. has faced strong opposition from Russia when it comes to addressing the seven-year-old war in Syria, and frustration from European allies over reimposing nuclear sanctions against Iran.
  
Trump said he was considering many candidates for Haley's job and that a successor would be named in two to three weeks - or maybe sooner.
  
The daughter of Indian immigrants, Haley clashed with then-candidate Trump during the 2016 campaign, denouncing "the siren call of the angriest voices" that disrespected America's immigrants. Trump tweeted that "The people of South Carolina are embarrassed by Nikki Haley."
  
"Before she was named by Trump to her U.N. post, Haley was elected the first female governor of South Carolina. She was re-elected in 2014. As governor, she developed a national reputation as a racial conciliator who led the charge to bring down the Confederate flag at the Statehouse and helped guide the state through one of its darkest moments, the massacre at a black church.
  
South Carolina Republican Sen. Lindsey Graham, a close Trump ally tweeted that Haley "has a very bright future and will be a key player in both the future of the Republican Party and our nation as a whole for years to come."
  
Sen. Bob Menendez of New Jersey, the ranking Democrat on the Senate Foreign Relations Committee, said Haley's leaving is "yet another sign of the Trump administration's chaotic foreign policy and setback from promoting American values and priorities."