Obama is NOT a pacifist.
He happily assassinated Gaddafi, turned Libya into a failed state. He didn’t mind seeing Egypt on the brink of civil war and genocide with his promotion of the Muslim Brotherhood. At bare minimum, he allowed and approved the change of government in Ukraine that was a direct stab at Russia’s multi-century interests in Crimea and the Black Sea.
He had no problem provoking opponents, or stirring the sh** in those places. So he is no pacifist interested in calming the waters of world politics.
So the question is then - what exactly is his goal with Iran?
Arming Iran with nuclear weapons to destroy Israel, of course. While saying all the right things everyone else wants to hear.