- "Is there anyone that believes that North Korea would agree to a ban on nuclear weapons?" Haley asked
- President Barack Obama's administration also opposed the talks
Flanked by ambassadors from about 20 nations, including nuclear powers United Kingdom and France, Haley couched the decision not to attend the talks, which began Monday, in personal terms.
As a mom and daughter, "there is nothing I want more for my family than a world with no nuclear weapons," the former South Carolina governor said. "But we have to be realistic."
"Is there anyone that believes that North Korea would agree to a ban on nuclear weapons?" Haley asked.
President Barack Obama's administration also opposed the talks, which the General Assembly voted to approve in December, and nuclear powers Russia and China also are not taking part. United Kingdom Ambassador Matthew Rycroft said his country also would not attend the talks because "we do not believe that those negotiations will lead to effective progress on global nuclear disarmament."
President Donald Trump told Reuters
last month that he would prefer a nuclear-free world, but otherwise the United States should be "at the top of the pack."
The boycott on Monday drew criticism from backers of the treaty, who called it "an unhelpful distraction."
"Today's last minute protest by Ambassador Haley and others standing with the American president demonstrates how worried they are about the real impact of the nuclear ban treaty," Beatrice Fihn, executive director of the International Campaign to Abolish Nuclear Weapons, said. "It is an unhelpful distraction from the important work of banning nuclear weapons."
Treaty supporters say the risk of a nuclear detonation are higher than at any time since the end of the Cold War.
But Haley said of the foreign officials joining the discussions, "you have to ask yourself, are they looking out for their people? Do they really understand the threats that we have?"
If adopted, the treaty would outlaw the use, possession and development of nuclear weapons and set up their eventual elimination.