From what I have read, it seems that it was N. Korea that walked away from the table, not the US.
Due to the potential threat, it is less likely that Japan will NOT develop its own nukes, which would increase the chances of a nuclear exchange in east Asia. That eventuality is not the fault of the president of the US, but he is foolish for being played as he has been.
Thus far in two years the most important US foreign policy moves have benefited the adversaries of the United States. The president tends to believe everything he is told by his good friends Xi and Kim, and his man-crush Mr. Putin will apparently be deploying new weapons targeted at his Komrade's country.