According to the United States North Korea is a serious threat.
White House National Security Adviser H.R. McMaster: North Korea is “the greatest immediate threat to the United States”[1]
President Donald Trump: North Korea is “a threat to the civilized world and international peace and stability.”[2]
You be the judge. Here are the numbers.
[1] http://edition.cnn.com/2017/12/02/politics/mcmaster-potential-war-north-korea/index.html
[2] http://www.presstv.com/Detail/2017/11/06/541176/US-Trump-Japan-Asia-Korea
[3] CIA World fact Book. https://www.cia.gov/library/publications/the-world-factbook/
[4] https://www.globalfirepower.com/defense-spending-budget.asp
[5] https://www.globalfirepower.com/countries-comparison-detail.asp?form=form&country1=united-states-of-america&country2=north-korea&Submit=COMPARE
[6] http://www.icanw.org/the-facts/nuclear-arsenals/
[7] David Vine: https://dra.american.edu/islandora/object/auislandora%3A55685