What's the current situation: USA was party to the multilateral agreement which aimed to stop the Iranian program for enrichment of uranium. The agreement was however never finally approved by the Congress due to the Republican resistance against anything Obama, and in order to keep USA in the agreement POTUS need to issue a monthly statement confirming that Iran stick to the agreement.
THIS IS OFCOURSE not an acceptable solution and the President need to come to Congress with something they can accept.
Middle East president elect and president Mr. Trump has been very consistent and adhered to the party line that the Iran deal was in fact a bad deal. That he therefore now pulls USA out of it should not come as a surprise.
MIDDLE EAST as bad as it seems. Trump probably sees the development regarding North Korea as a success for his hard-line approach and see no reason to stop. It is a negotiating tactic. He wants to be able to claim he got better deals for the USA than anybody else could.
To compare the two would be dangerous. However, as witht the Paris agreement and NAFTA the USA could join agian just as casually as they exited. President Trump just need to get a success and admission to be able to turn back.
The short term consequence for an investor is ......
Middle east leaders are betting that Xi exceeds Trump on longevity.