Mr. Kim, however, signaled no such openness. In a statement, he denounced Mr. Trump as a “rogue and gangster fond of playing with fire” and said that rather than deter him, Mr. Trump’s speech had convinced him that “the path I chose is correct and that it is the one I have to follow to the last.” He vowed retribution: “I will surely and definitely tame the mentally deranged U.S. dotard with fire.”
Mr. Kim on Friday vowed the “highest level of hard-line countermeasure,” in response to Mr. Trump’s speech. Asked by reporters in New York what the North Korean might intend, his foreign minister, Ri Yong-ho said that he thought the North might be considering the largest test of a hydrogen bomb ever in the Pacific Ocean, according to the South Korean news agency Yonhap.
But it has withstood an array of American and international sanctions for years, and it remains unclear whether the latest round will have any greater effect. Just last week, the United Nations Security Council approved an American-drafted resolution tightening limits on North Korean trade, although it did not go as far as the Trump administration wanted.
Some critics of Mr. Trump praised him on Thursday for focusing on diplomatic pressure rather than saber rattling. R. Nicholas Burns, a former undersecretary of state under President George W. Bush, said the new American sanctions were “a smart move” because the latest United Nations resolution was insufficient.
“The U.S. sanctions will help to raise the cost to North Korea of its nuclear weapons buildup,” said Mr. Burns, who now teaches at Harvard. Referring to the United Nations Security Council, he added: “The Bush and Obama administrations pursued a similar path on Iran sanctions — both U.N.S.C. and American unilateral sanctions — which proved effective.”
David S. Cohen, who directed sanctions for President Barack Obama at the Treasury Department, was impressed. “I think it is reasonably significant,” said Mr. Cohen, who now works on sanctions issues at the…