1. Trump's decision just made the world a more dangerous place in ways that begin with Iran's nuclear program but go far beyond it.
2. To begin with, without the constraints in the JCPOA, Iran's nuclear program could once again approach the point where they have enough fissile material for a nuclear weapon. Scenarios that deal opponents warned about 10-15 years from now would come much quicker.
3. The U.S. could then be faced with the choice of accepting a de facto Iranian nuclear capability or going to war to stop it.
4. Given how much Iran took advantage of the catastrophic decision to invade Iraq, any conflict with the U.S. could threaten our interests in Israel, Lebanon, Syria, Iraq, Yemen and beyond
5. Inside of Iran, Trump just gave hardliners an opening to strengthen their position in ways that could negatively shape the succession process when Iran's aging Supreme Leader dies
6. Outside of Iran, Trump just initiated a crisis with our European allies that at a minimum makes it harder to cooperate to confront Iranian behavior. Beyond that, could be a widening rift in the relationship that infects other issues and undermines our closest partnership
7. In North Korea, it's hard to see Trump achieving a deal as good as the JCPOA (which he calls a disaster), and he just also alienated China and Russia who will be important to our North Korea diplomacy
8. Together with TPP and Paris, Trump's action also severely undermines the credibility of the United States to uphold international agreements that we sign which will endure after he is gone
9. The U.S. role at the center of the international order - especially our leadership of the nuclear non-proliferation regime - is set back given that the JCPOA was anchored in our commitment to the NPT
10. Trump's potential efforts to enforce secondary sanctions could face stiff resistance from Europe and Asia, more broadly undermining the efficacy of sanctions as a tool of U.S. policy and potentially the role of the dollar as the reserve currency
11. China will continue its subtle but effective global effort to cast the U.S. as unreliable, pressing its alternative view of global arrangements that suit its interests
12. Finally, at home he has turned the gravest national security issues into a political reality show, poisoning the discourse on serious issues
13. All of these risks for no reason, based on no understanding of the Deal, simply because Barack Obama was involved in negotiating it.
