WASHINGTON,OCT 10:Nikki Haley was appointed to the UN post in November 2016 and last month coordinated Trump’s second trip to the United Nations, including his first time chairing the UN Security Council. Nikki Haley will leave her job as US ambassador to the United Nations at the end of the year, President Donald Trump said at the White House on Tuesday.Trump said Haley told him six months ago she wanted a break after spending two years in the post. “She’s done a fantastic job and we’ve done a fantastic job together,” Trump said.Haley is a former governor of South Carolina who has repeatedly deflected speculation that she might harbor presidential aspirations of her own. “It has been the honour of a lifetime,” she said in the Oval Office, thanking Trump.“No, I am not running in 2020,” she said. She would campaign for Trump, she added.Haley’s decision startled White House Chief of Staff John Kelly and Vice President Mike Pence, officials said. Trump teased an announcement less than 15 minutes before his appearance with Haley, after news organizations began reporting she would resign.Big announcement with my friend Ambassador Nikki Haley in the Oval Office at 10:30am.Her resignation was first reported by Axios. Several senior White House aides wondered about.the timing of her decision, weeks before midterm congressional elections. Trump said he’d name a successor in two to three weeks or sooner.One potential replacement is Goldman Sachs Group Inc. partner Dina Powell, a former Trump adviser who left the White House earlier this year, two people familiar with the matter said.Haley has been a strong advocate of Trump’s foreign policy. On her first day as UN ambassador she warned, “for those that don’t have our back, we’re taking names. We will make points to respond to that accordingly.”She’s been one of the more effective members of Trump’s cabinet. As UN envoy, she was credited with rallying the Security Council to ramp up sanctions on North Korea as it increased its nuclear weapon and ballistic missile tests last year. Those sanctions are now under strain, but the administration says they forced Kim Jong Un to the negotiating table.U.S. ambassadors to the UN typically serve short terms. Haley will have served longer than five of the last 10 people who held the job.After a frosty relationship with Rex Tillerson, Trump’s first secretary of state, she and Tillerson’s successor, Mike Pompeo, often exchanged mutual praise.She backed Trump’s efforts to cut off funds for the UN organization that aids Palestinians and joined in his attacks on Iran. But she also hinted at her disagreements with the president, saying she had a “personal conversation” with Trump about his response to white supremacist violence in Charlottesville, Virginia, last year.Haley has repeatedly insisted that she’s focused on the job at hand, not future opportunities, in response to the speculation about her political ambitions.After an anonymous U.S. official published an op-ed last month declaring that there was an internal resistance to Trump’s policies, Haley published her own op-ed in the Washington Post declaring her fealty to the president.“I don’t agree with the president on everything,” Haley wrote in her Sept. 7 op-ed. “When there is disagreement, there is a right way and a wrong way to address it. I pick up the phone and call him or meet with him in person.”Tensions bubbled up between Haley and Trump in April when Vice President Mike Pence hired a long-time Haley aide and Republican pollster as his national security adviser, prompting speculation that Haley and Pence were forging a political alliance, White House advisers said. The aide, Jon Lerner, who was planning to split his time between working for Haley and Pence, withdrew his name from consideration after backlash from within the White House.Trump advisers outside the White House have assumed Haley would have her own presidential aspirations at some point, but doubt she would mount a run against Trump in 2020.