Donald Trump’s appointment of Heather Nauert – the state department spokeswoman and a former Fox News anchor – as the new US ambassador to the United Nations is widely being interpreted as bad news for the UN.

Unlike the current ambassador, Nikki Haley, Nauert is not expected to be given cabinet status, downgrading the role to being largely a mouthpiece for the secretary of state, Mike Pompeo, and the national security adviser, John Bolton – both of whom are deeply sceptical of the UN’s usefulness.

With no policymaking or negotiating experience, and after 20 months as a spokeswoman for the state department, Nauert will take her seat on the security council alongside counterparts with decades of experience. Haley was also a diplomatic novice – though she did arrive in New York with the six years experience of running South Carolina as governor.

During Nauert’s tenure at the state department, press briefings went from being daily events to being held once or twice weekly. Nauert was mostly a polished and unflappable defender of administration policy, smoothing over frequent rifts between the Trump’s first secretary of state, Rex Tillerson, and the White House.

But her inexperience sometimes shone through: in June she cited the D-day landings as evidence of the longstanding relationship between Washington and Berlin.

“When you talk about Germany, we have a very strong relationship with the government of Germany,” Nauert said, adding: “Tomorrow is the anniversary of the D-day invasion. We obviously have a very long history with the government of Germany, and we have a strong relationship with the government.”

Nauert, 48, rose to fame at the time the Monica Lewinsky sex scandal threatened to bring down Bill Clinton’s presidency, joining Fox News as one of a chorus of presidential critics.

“I told her, ‘God made you beautiful. Now you’ve got to make yourself smart,’” Tony Snow, a Fox News host told the Washington Post in 2000. “TV can be a blond wasteland. There are a lot of gorgeous people with only one thing to say who vanish from the scene.”

Nauert became an anchor on Fox & Friends, Trump’s favourite television talkshow, where she helped air the network’s recurrent themes about the threat of immigration, warning that immigrant children arriving in the US could be bringing disease into the country, and that Sharia law was spreading in urban areas with Muslim populations.

On the other hand, while mostly toeing the administration’s line at the state department lectern, she has spoken out strongly in support of journalism, at a time the president has referred to the press as the “enemy of the people”, and called for accountability for the massacre of Rohingya civilians by Burmese forces while the administration dithered over whether to call the mass killings a genocide.

Nauert will arrive at the UN at a time when the Trump’s administration’s attitude to the organisation, always sceptical, is turning disdainful following the arrival of Bolton in the White House in March. The former US ambassador to the UN once said that if you lopped off the top 10 floors of the organisation’s New York headquarters, it would make no difference.

Pompeo was scathing about the UN in a speech this week in Brussels.

“Today at the United Nations, peacekeeping missions drag on for decades, no closer to peace,” he said. “The UN was founded as an organisation that welcomed peace-loving nations. I ask: today, does it continue to serve its mission faithfully?”

Haley was also an outspoken UN sceptic, but developed a working relationship with the secretary general, António Guterres, which helped protect US funding from hawkish demands for deep cuts from Washington. Since Haley announced her departure, the US has become more aggressive in insisting budgets for UN peacekeeping operations in Africa be frozen or cut.

“The balance between Nauert’s ambition and autonomy will be interesting,” Ashish Pradhan, the International Crisis Group’s senior UN analyst, said. “Haley had a lot of autonomy, with Tillerson largely absent, she had the ambition and leeway to drive US policy.

“Those days are definitely behind us, especially since Pompeo and Bolton joined,” Pradhan said. “For Nauert it is going to be more about implementing than developing policies.”