Editor’s Note: Stephen Schlesinger is a fellow at the Century Foundation and author of “Act of Creation” about the founding of the United Nations. The views expressed in this commentary are his own.

CNN  — 

The US Ambassador to the United Nations, Nikki Haley, is going through one of the roughest patches in her public career. She still appears on the front pages with pronouncements at the UN, but her star, which was burning so brightly in the first year of the Trump administration, is beginning to dim significantly in the second year.

Here are some of the things which have put a dent in her stature. Haley did not attend the summit in Singapore between President Donald Trump and Kim Jong Un. Though it’s unclear whether she was included in preparations or even invited, her absence was quite noticeable. Haley had been one of Trump’s first choices for a top-level foreign policy position, had been granted Cabinet-level rank by Trump as his UN envoy and tasked by him to push his “America First” policies at the UN. And, in fact, she led the fight in the UN Security Council to successfully impose stricter sanctions on North Korea, citing it as one of her accomplishments. Yet, in this, Trump’s most important foreign policy foray of his presidency, she may have been left out.

Stephen Schlesinger

She also missed out on another symbolic moment in the Trump saga – she did not attend the ceremonial opening of the US embassy in Jerusalem. She had championed Trump’s decision to move the embassy against fierce opposition both in the UN Security Council, where her veto of a resolution condemning the event was a lone vote blocking it (14-1), and in the General Assembly, where only eight other countries backed her attempt to refute a similar critical declaration. Some 128 nations voted for it and another 56 nations did not vote or abstained. Afterward, Haley went to great trouble to hold a reception for those few countries that had supported Washington to emphasize America’s anger over its treatment at the UN.

Most recently, upheavals in Washington have now left her as the odd woman out in Trump’s foreign policy’s team. This has been a remarkable turn-about for, in Trump’s first year, Haley outshone Trump’s Secretary of State Rex Tillerson, National Security Adviser H.R. McMaster and Secretary of Defense James Mattis – all grey men with little visibility – with her vivacity, her skill in the media and winning television personality. Indeed, she even appeared, at times, to be pursuing her own foreign policy at the UN due to the continuing distractions and personnel reductions at the State Department and Trump’s focus on domestic matters. Time Magazine put her on the cover as one of the most important “women who are changing the world.”

But over the last several months, the President has replaced two of his three top national security figures – John Bolton as the new National Security Adviser and Michael Pompeo as the new Secretary of State. These two men are hard-headed bureaucratic in-fighters – Pompeo a former CIA director and congressman of deeply conservative convictions and Bolton a far-right ideologue. Both are also savvy operators in the media and are based in Washington DC, making them closer to Trump than Haley is. Trump, indeed, has said he likes Pompeo’s manner and, while Bolton has no intimate ties to the President, he is just down the hall from Trump in the White House. Neither man is likely to give Haley any further free rein at the United Nations.

Haley’s freshness on the world scene may also be turning a bit shopworn. Once a semi-independent representative in New York, she appeared distinct from old-time Washington diplomats. She even differed with Trump, on occasion, over Russia regarding Syria and the Ukraine, in defending the UN, and in disagreeing, for example, over the Charlottesville march. But gradually, she has started to take on the role of attack dog for Trump at the UN, stridently espousing his “America First” position against the Paris accord on climate change, the Iranian nuclear deal, further US funding for the UN and any US membership in the UN Human Rights Council.

But she has also begun to run afoul of Trump in public ways. For example, one of her top aides, Jon Lerner, was supposed to get a White House position as National Security Adviser to Vice-President Mike Pence, but he withdrew when Trump found out Lerner had worked for Sen. Marco Rubio during the campaign and may have been connected to opposition research against him. On another occasion, Haley announced on a Sunday news show that the administration was about to impose a new round of sanctions on Russia. The next day Trump dismissed the sanctions, placing Haley in the awkward position of looking out of step with her boss.

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    Adding to Haley’s discomfort, there has been continuing uneasiness over her purported ambitions to run for the presidency. Trump once joked to a gathering of UN Security Council envoys that they should let him know if they don’t like Haley because she “can be easily replaced.” This was supposed to be a funny though sly reminder about who exactly is the head man in this government – but it came across as a not-so-subtle warning to Haley not to get ahead of her skis on her job.

    Where does this leave Haley today? Having achieved great visibility as the US ambassador to the UN, she might at some point have to consider resigning from her post to give her the space to decide on a possible presidential run. Or she could tough it out at the UN through 2020 and then ask for a higher role if Trump gets a second term. Some might even say that she could use her Cabinet access to Trump more aggressively. The sorry fact, though, is that Trump no longer relies on her as his leading foreign policy expert. He has Pompeo and Bolton for that.