Take a look at what President Obama said in an interview with the BBC’s Jonathan Sopel after Sopel noted that lifting sanctions in Iran would mean greater resources for Hezbollah and the Assad regime in Syria and would have the affect of further destabilizing the Middle East:
Well, keep in mind, first of all, we’ve shut off the pathways for Iran getting a nuclear weapon, which was priority number one. Because if Iran obtained a nuclear weapon, then they could cause all those same problems that you just listed with the protection of a nuclear bomb. And create much greater strategic challenges for the United States, for Israel, for our Gulf allies, for our European allies.
Second, it is true that by definition, in a negotiation and a deal like this, Iran gets something out of it. The sanctions regime that we put in place with the hope of the Brits, but also the Chinese and the Russians and others meant that they had funds that were frozen. They get those funds back. A large portion of those funds are going to have to be used for them to rebuild their economy.