"She's [Nauert is] going to work with Nikki Haley to replace Nikki at the United Nations".
"It will have to do with the joint chiefs of staff, the succession", he told reporters outside the White House, suggesting he may name a new top US military officer. "I have great confidence in her".
Nikki Haley has held the United Nations post since the beginning of Trump's administration and said she would stay in the job through the end of the year.
Nauert is to replace Nikki Haley, the former SC governor who announced in October that she would step down as ambassador at the end of this year.
In 2016, she tweeted a New York Times story on Muslim Americans' concerns about the rise of Trump, writing: "Omg-They should meet #ISIS".
Before joining the State Department, Nauert was an anchor and correspondent at Fox News.
During her tenure as a State Department spokeswoman, Nauert largely stuck to the department's official script, often deflecting questions about USA allies, including Israel.
While Nauert must still be confirmed by the US Senate, Benjamin said she will easily get the approval of the Republican-controlled chamber.
Nauert needs a simple majority to be named the ambassador and will be questioned by Democrats in the Senate.
It's more a matter of the personal clout of the person holding the position, vis-à-vis the nominal figures directing USA foreign policy like the secretary of State and the president's national security adviser - the two people Jonathan Swan cites as insisting on Nauert's non-Cabinet rank.
After her appointment as acting undersecretary, she was for a time the highest-ranking woman and fourth highest-ranking official at State.
Aaron David Miller of the Wilson Center says Nauert has a different profile from past US ambassadors to the United Nations. I think about sleeping in. I do. She will learn the brief. Since Haley announced her departure, the United States has become more aggressive in insisting budgets for UN peacekeeping operations in Africa be frozen or cut.
In announcing his decision today, Trump said Nauert was "very talented, very smart, very quick".
White House press secretary Sarah Huckabee Sanders described Nauert in March as "a team player" and "a strong asset for the administration".
However, Haley admitted she and the president "agree on most things", but "there are certainly things that we don't agree on".
"With Pompeo more firmly in control and Bolton focused on his anti-multilateral agenda, there's a sense the U.S. ambassador will have less clout", Gowan said. The former SC governor served almost two years in the post and was the first Indian-American appointed to a Cabinet position in any USA presidential administration.
Other than her 20-month run as the top spokesperson at Foggy Bottom, Nauert has no diplomatic experience.
Unlike Haley, however, Nauert is not expected to have cabinet status, keeping power over foreign policy firmly with Pompeo and especially John Bolton, the hawkish White House national security advisor.
With her vast expertise in TV journalism, including eight years at Fox News and at least three at ABC, Ms Nauert certainly knows how to behave in public and deliver neat and well-targeted speeches.