Kelly Craft was on Wednesday confirmed by the US Senate as the country's next ambassador to the UN, hours after a report warned that she was unqualified and should not be given the job.
Nominated by President Donald Trump in May, Mrs Craft, 57, will succeed Nikki Haley as head of the US mission to the UN in New York. Ms Haley left in December last year.
Testimony given by Mrs Craft to the Senate foreign relations committee in June failed to convince doubters, who said her answers showed she lacked experience in global affairs.
Democrats also said she had failed to display leadership as US ambassador to Canada, given the great amount of time she had been absent from her post.
Leading the US mission to the UN would be an “insurmountable hurdle” for Mrs Craft, members of the committee said in a seven-page document, calling her a "diplomatic novice”.
Her main qualification for the role, they claimed, was that she and her husband were political donors to Republican politicians.
The couple reportedly gave more than $1 million to Mr Trump's 2016 election campaign.
“Ambassador Kelly Craft’s qualifications fall short," they wrote.
"She does not have the knowledge, skills, qualifications or experience to successfully lead the United States’ efforts at the United Nations.
“This position requires someone who can stand up to the toughest of adversaries, who can deftly negotiate on a global stage without compromising our principles, and who can effectively advocate on behalf of those who do not have sufficient voice in the world.
"Regrettably, Ambassador Craft is not that individual.”
It emerged that as ambassador to Canada since October 2017, she had been outside the country for more than half that time, including 43 trips to Kentucky and Oklahoma where she and her husband, coal billionaire Joe Craft, have homes.
And on diplomatic matters and foreign policy she appeared unseasoned, unlike past holders of the UN post such as George H W Bush, Richard Holbrooke and Madeleine Albright.
“When asked about the most pressing issues the UN faces and how the United States can leverage the UN to pursue our national foreign policy priorities, Ambassador Craft did not mention the major crises or complexities facing the United States today," the senators said.
They said she did not speak of threats from North Korea and Iran, the growing influence of China and Russia, the political and economic meltdown in Venezuela or the situation in Libya.
“When asked about the two-state solution, which has been the cornerstone of US policy concerning the Palestinian-Israeli conflict for years, she could not articulate a coherent or succinct viewpoint,” they said.
The Trump administration had wanted the UN post filled before the opening of the General Assembly in late September, and before Congress starts its six-week summer break.
Mrs Craft was Mr Trump's second choice for the post after his first pick, former State Department spokeswoman Heather Nauert, withdrew because of family reasons.
The appointment comes after heavy criticism of the world body by Mr Trump and the withdrawal of the US from key initiatives including the Paris Climate Accord and the UN's Global Compact on Migration.
But with efforts to address climate change among the UN's most significant programmes, Mrs Craft said that given her family's fortune in coal she would step back from some discussions.
"I will give you my commitment that where coal is part of the conversation within climate change at the UN, I will recuse myself," she said in June.
"I understand that this is an issue that needs to be addressed. I also understand that fossil fuels have played a part in climate change."
A spokesman for UN Secretary General Antonio Guterres welcomed Mrs Craft's appointment.
“We look forward to having a permanent representative of the United States and the Secretary General looks forward to working with that person in a constructive way,” the spokesman said.