Trump thinks about leaving the Paris Climate Agreement. The only thing Trump wants is to spend less on things that make the USA spends money on and isn't getting enough in return. He would only be keeping things that let USA gain money through investments. This would be agreements like UN (since this gives USA major veto power) and NORAD (mexico and canada are huge trading partners). He made it clear that he wants to make america great again. Now, I'm no trump supporter (i'm from Canada) but i think this would be good since usa and canada wouldn't have to be involved with european conflicts. EU would probably make another zone called the European Military Area or something like that. Denmark would probably not be able to join since Canada and Denmark would probably wage a war without NATO. And so that is my opinion.
Trump is not about disbanding NATO, however he does see the dangers of an unelected military power that has the potential of subverting the will of the people.
NATO has entwined itself with the will of powerful, greedy multinational corporations who are playing a game of Risk with WW3. Us people understand this, and so does Trump. NATO's greed for power and wealth is fueled by billionaires who want more wealth, more power, more worship, and better sex. It's the same lust, generation by generation, century by century, millennium by millennium. Do you think they have changed and want to sing Koombaya with the serfs in 2017? You are sadly mistaken.
Without USA Nato is doomed. USA is using 73% of NATO's troops and imports 40% of food and economic things. So USA is very efficient and needed to NATO. USA has the biggest GDP and economy in the world and it's a good thing to help each other. Without Trump and USA it's hard for Germany, France, Austria, The Netherlands and the UK.