The first and most important thing to understand about Obama's Iran policy is that it is driven primarily by the concerns of Saudi Arabia, not Israel, as the media and diplomats would have you believe.
While Israel is most visibly in Iran's nuclear sights, it is commonly understood in the Middle East that the path to leadership of the Arab, and by extension Muslim world, lies through the destruction of Israel. The consensus of the Sunni Muslim powers, who had lost several wars to Israel, was to limit themselves to proxy wars through the sponsorship of terrorists such as the PLO.