Nikki Haley Resigns as U.S. Ambassador to the United Nations

As ambassador, Ms. Haley was an outspoken and often forceful envoy — someone whom foreign diplomats looked to for guidance from an administration known for haphazard and inconsistent policy positions. She was quick to voice her own opinions on the big policy issues that are high on her agenda, like Iran and North Korea.

Ms. Haley acknowledged her policy disagreements with the president in an op-ed in the Washington Post last month when she criticized an anonymous senior administration official who penned an opinion piece in The New York Times, describing a chaotic administration in which many of the president’s aides disagreed with their boss.

“I don’t agree with the president on everything,” Ms. Haley wrote. “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.”

Ms. Haley also collided with the national security adviser, John R. Bolton, after she announced that Mr. Trump would lead a session of the United Nations Security Council devoted entirely to Iran. After European officials protested that this would showcase divisions in the West because of Mr. Trump’s decision to pull out of the Iran nuclear deal, the White House broadened the theme to countering weapons of mass destruction.

Mr. Bolton did not criticize Ms. Haley. But as a former ambassador to the United Nations, he drove the decision to shift the agenda. White House officials noted that under United Nations rules, Iran would have been entitled to send its president to the meeting — setting up the awkward possibility that Mr. Trump would have sat across a table from Iran’s leader.

Ms. Haley also has cast herself as someone able to sway her mercurial boss on issues like Russia sanctions, refugee resettlement and the value of the United Nations itself.

She was the first cabinet-level United Nations ambassador for a Republican administration since the end of the Cold War, and quickly made clear she saw the position as a steppingstone to a higher political office — a possibility that Mr. Trump may have resented.

She became a far more visible face of American foreign policy than her first boss at the State Department, former Secretary of State Rex W. Tillerson. Time magazine celebrated Ms. Haley’s ascendance by putting her on a cover as one of the women who are “changing the world.”

A March 9 article in Foreign Policy magazine, in an article titled “Candidate Haley,” portrayed her as a “retail politician turning U.N. diplomacy into a ticket to the White House.”

While Ms. Haley was among the few women in Mr. Trump’s cabinet, she is far from the first United States woman to hold the United Nations ambassador position. She succeeded Samantha Power and Susan E. Rice, who both worked for former President Barack Obama.

Other women envoys from the United States to the world body have included Madeleine Albright, Jeane Kirkpatrick, Anne Patterson, Rosemary DiCarlo and Michele Sison.