American and Israeli opponents of the agreement between the six major powers and Iran over the latter’s nuclear program have come up with dozens of arguments why the deal is bad. Many of them emerged before the deal existed. But of these reasons, a few have gained wide currency. One of these is the idea that Iran is poised to dominate the Middle East. In remarkably similar language, Israeli government officials, Republican congressmen and presidential candidates, and hawkish pundits all argue that détente on the nuclear issue will turn the region over to Tehran.