Since North Korea has a mad man at the helm, with or without Trump the situation is worrying.Some take the view that America doing and saying nothing much for so long is what has allowed North Korea to build up their nuclear programme.
China, at long last is backing the new sanctions.
Trump doesn't act alone, and has some good military advisors, so although his message may ( or may not) have been advisable, any action will be well considered.
I am not a fan of The Donald in any shape or form and was rooting for Clinton to win, but he has inherited this situation from years of a softly softly approach in regards to N Korea.