The Trump administration is terrible at assessing foreign threats:
#BREAKING  North Korean nuclear weapons 'existential threat' to US: intelligence chief
— AFP news agency (@AFP) February 13, 2018 
If Dan Coats believes that North Korea’s arsenal is an “existential threat”  to the U.S., he has no idea what the phrase means and his judgment shouldn’t be trusted. Perhaps he doesn’t really believe this, but thinks this is a good way to frighten members of Congress and the public into going along with a bankrupt North Korea policy. In that case, he should also be ignored. There are maybe two other states that could cause the destruction of the United States with their nuclear arsenals, and they would be destroyed in the process by ours. Otherwise, there are no foreign existential threats to the U.S. Referring to North Korea’s nuclear weapons as an existential threat is completely wrong, and it is deeply irresponsible fear-mongering on the part of the Trump administration to make this claim. The only reason I can think of to make such an unfounded and false claim is to build support for an attack.
Threat inflation is one of the most pervasive and harmful parts of our foreign policy discourse. Manageable threats are blown out of proportion, deterrable adversaries are transformed into irrational, unstoppable menaces, and limited dangers are exaggerated beyond recognition. That not only encourages ever-higher levels of unnecessary military spending, but it also generates unwarranted fear about the security of the country. That allows our political leaders to maintain aggressive policies that have nothing to do with the defense of the United States, and it leads them to embrace reckless and outrageous policy ideas, including preventive war, to “solve” problems that don’t exist.