They're conning you. None of the countries you mentioned would risk a nuclear war which they know would be suicidal.  Period. China and Iran have never threatened the United States, but will defend their territories if the US attacks. And they will do it with much less military spending.  Kim likes to rave, but in no way is a threat to the US either, again unless the U.S.  attacks.
 ISIS is at most, a regional threat in countries that the US invaded but couldn't finish the job.