Along with the ongoing process of normalizing relations with Cuba, this move shows that diplomacy can produce peaceful, positive changes. It also shows that sometimes taking a principled position means facing down overwhelming opposition from all sides and not backing down. The president should be commended for both of these achievements.

The agreement has reduced the chance of a US attack on Iran, which is a great development. But the interventionists will not give up so easily. Already they are organizing media and lobbying efforts to defeat the agreement in Congress. Will they have enough votes to over-ride a presidential veto of their rejection of the deal? It is unlikely, but at this point if the neocons can force the US out of the deal it may not make much difference.